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D-Geo Stability User Manual - Parent Directory

1. 129 8 15 Project Properties window General tab 129 8 16 Points window 1 a a a 130 8 17 Pl Lines window a a a 131 8 18 View Input window with new phreatic line 132 8 19 PL lines per Layer window 2 2 2 132 8 20 Information window 1 6 ee a 133 8 21 Materials window 1 a a a a 133 8 22 Slip Circle Definition window 134 8 23 Start calculation window a a a a a a 135 8 24 Progress of Calculation window 1 a e 136 8 25 Report window a 137 8 26 Stresses in Geometry window 138 8 27 Critical Circle window Slip circle with lowest safety factor 139 8 28 Stress mode toolbox 29 Wh 139 8 29 Shear stresses window along the slip circle 140 8 30 FMin Grid window 1 6 ee a a a a 140 8 31 Safety Overview window a a a a a 141 8 32 Construction of a berm Tutorial 1D lll ln 142 8 33 Lower left corner of View Input window 142 8 34 View Input window Geometry tab Berm construction points 143 8 35 Point 11 properties window 143 8 36 Layer 5 properties window 144 8 37 Safety Overview window a e a a a 144 9 1 Dike with lowered water level Tutorial 2
2. 99 42 4 Model Factor A o8gg g s o o o o ee eee 57 Geometry menu MY A 57 43 1 New Rm 4 57 4 3 2 New Wizard Wypg y 58 43 3 Import WM osse 98 4 3 4 Import geometry from database 58 43 5 Export QE WW LLL 99 4 3 6 Export as Plaxis DOS W MA oo 59 4 3 7 Limitts V 4 59 43 8 Points MB 60 4 3 9 Import PL line 4 29 WH 2 eee ee aa 61 4 3 10 PLlines BY A WHR 2 ee ee ee 61 4 3 11 Phreatic Line Pal MY lt 62 4 3 12 Layers 428 GD 9 2222s 62 4 3 13 PL lines per Layer 63 4 3 14 Check Geometry 2 2 2 2 65 Definitions menu a aoao a a a a a a 65 4 4 1 Slip Plane Definition a 65 4 4 1 1 Slip Circle Definition Bishop or Fellenius 66 4 4 1 2 Slip Plane Definition Uplift Van Uplift Spencer 67 4 4 1 3 Slip Plane Definition Spencer 68 4 4 2 Calculation Area Definition 70 4 4 3 Forbidden lines rcr 71 4 4 4 Zone Areas for Safety 00 nn 71 4 4 5 Reference level for Ratio CUPPC 0 73 Reinforcements kee 6 wow ee Ee asa a ee 73 45 1 Geotextiles 2 73 4 5 2 Na
3. l l Example of deletion of a point lll Example of deletion of a geometry point Example of deletion of a line Pop up menu for right hand mouse menu Select mode layer window Property editor ofalayer 8 Point window Property editor of a point Boundary window Property editor of a polyline Boundary window Property editorofaline PL line window Property editor of a PL line Example of dragging of a point Water retaining dike Tutorial 1 New File window a New Wizard window Basic geometrical properties New Wizard window Basic geometric situation New Wizard window Top layer measurements New Wizard window Soil selection New Wizard window Geometry overview View Input window 6 6 ee ee a Model window 1 1 1 we a a Project Properties window Identification tab Project Properties window View Input tab xiii D GEO STABILITY User Manual XIV 8 12 Project Properties window Stresses Results tab 128 8 13 Project Properties window FMin Grid Resultstab 128 8 14 Project Properties window Safety Results tab
4. Deltares sustems Deltares D GEO STABILITY Slope stability software for soft soil engineering User Manual Version 15 1 Revision 00 23 September 2015 D GEO STABILITY User Manual Published and printed by Deltares telephone 31 88 335 82 73 Boussinesqweg 1 fax 31 88 335 85 82 2629 HV Delft e mail info deltares nl P O 177 WWW https www deltares nl 2600 MH Delft The Netherlands For sales contact For support contact telephone 31 88 335 81 88 telephone 31 88 335 81 00 fax 31 88 335 81 11 fax 31 88 335 81 11 e mail sales deltaressystems nl e mail support deltaressystems nl WWW http www deltaressystems nl WWW http www deltaressystems nl Copyright O 2015 Deltares All rights reserved No part of this document may be reproduced in any form by print photo print photo copy microfilm or any other means without written permission from the publisher Deltares D GEO STABILITY User Manual Deltares Contents 1 General Information LL FONO lt a s xe BE Ede E EOS owe ee ee ee ee 1 2 Preface amp 22 9x Dcwok ee POwoX X x d o3 4 4 d ok 36 ded dox x 133 Features in standard module 13 4 Soil modeling 2 rrr 1 3 2 LOS 2 23 99 55 xo BG beak nH GG o s 1 3 8 Slip plane determination 1 3 4 Results 40 a viendo 0 em a 1 4 Features in additional modules 1
5. 147 9 2 View Input window Geometry tab Adding of three points on the phreatic line 148 9 3 Point 20 properties window 2 149 9 4 View Input window Geometry tab New phreatic line 149 95 Materials window 2 2 2 2 2 2 2 252 2D2525 5 150 9 6 Slip Circle Definition window 151 9 7 Critical Circle Window lll lll 151 10 1 Dike reinforced with geotextile Tutorial 3 153 10 2 Model window a a 154 10 3 Geotextiles window 1 a a a 155 10 4 View Input window saoao a a 155 10 5 Critical Circle window a 156 11 1 Dike with different water levels at either side Tutorial 4 2 157 11 2 New File window a 158 11 3 View Input window Geometry tab after importing geometry 159 11 4 Model window 1 a 159 11 5 Program Options window Locations tab ls 160 11 6 Materials window Database tab 161 11 7 Information window 2 2 2 2 2 2 22525 252 5 161 11 8 Materials window Parameterstab 00 cll ll 162 11 9 PL lines per Layer window a 162 11 10 Degree of Consolidation window 163 11 11 Uniform Loads window 2 2 2 2 164 11 12 View Input window Input tab Tutorial 4a rs 165 11 13 Slip Pla
6. 2 2 2 2 Critical Circle window lll llle les n Slice Result window 2 2 2 2 2 2 2 252 52 Critical Plane window for Uplift Van method Critical Circle window for probabilistic analysis textitFMin Grid window Ae oo ro one Safety Factor per Zone window aa a a a a a a Critical circle window for the Zone plot model Influence Factors window 6 6 a a c Safety Overview window 1 ee a View Inout window Geometry tab View Input window Geometry tab legend displayed as Layer Numbers Legend Context menu ll hL View Input window Geometry tab legend displayed as Material Numbers View Input window Geometry tab legend displayed as Material Names Legend Context menu for legend displayed as Materials Color window 94 View input window Geometry tab Right Limit window WA Will Representation of apolyline Examples of configurations of polylines Modification of the shape of a berm Example of invalid point not connected to the left limit Selection accuracy as area around cursor l l Selection accuracy as area around cursor l l Selection accuracy as area around cursor
7. hi Slice height m ti Slice width m Ci Cohesion along slip surface KN m F Safety factor GL Weight kN Pr Interslice force kN N Effective normal force at bottom KN Foi Shear force along the bottom kN Fui Water force on slope kN L Length of sliding plane m W Water pressure against bottom kN T Distance interslice force sliding plane m Deltares 219 of 264 D GEO STABILITY User Manual Calculation of the interslice force Fy at intersection 2 tan p tan p sin a 0141 Fig cos a Fiia costs 01411 S Fy sin a Bj G sin o T 7 16 36 The interslice force is considered as a resultant of three forces acting on a slice side shear force along this side effective normal force water force The angle of interslice forces of the first and last fictitious interslice force is set to zero implying horizontal forces The angles of the other forces are set to 0 The fictitious interslice force acting on the first slice is zero Now the fictitious force needed to ensure equilibrium at the end of the slide plane can be calculated By considering the equilibrium of moments round the center bottom point of the slice the position of the resultant of interslice force is found in the following way Eo desi COS 0 4 Xia zs 0 5Ax tan Qi fel 1 sin 0 Ax Fy COS 0 0 5A zc fy sin Fy sin D F COS 0 16 37
8. m 5 000 Number Number le Tangent line Y top m 7 000 Automatic at boundaries bottom m 3 000 Humber 3 Cancel Help Figure 12 8 Slip Plane Definition window 32 Click OK The entered specifications will result in the calculation set up as seen in Fig ure 12 9 geses 178 of 264 Deltares Tutorial 5 The Uplift Van model EE 1441 BERETE c del LUTENI 4444 Tir TEE ae Fae Pa TE T4431 TITRE tt1441 Ji n x 64 000 9 750 E dit Current object None Figure 12 9 View Input window Input tab 12 7 Calculation and Results 34 Click Start in the Calculation menu 35 Click OK to perform the calculation 12 7 4 Stresses To view the shape of the slip surface 36 Click Stresses in the Hesults menu to open the S ip Plane window In the window displayed Figure 12 10 the measurements of the slip surface can be seen It consists of two partial circular slip surfaces connected by a line As with the Bishop method each slip circle has a grid that has moved from its original position The safety factor is equal to 1 81 The number in brackets 1 72 indicates alternative safety factor In a reliability analysis the model factor is applied to the calculated safety factor to produce the alternative safety factor The model factor represents the uncertainty in the required safety factor This reduces the safety factor in the following way Fcalculatea Model Factor In this case th
9. 158 of 264 Deltares 11 2 2 11 2 3 Tutorial 4 The Spencer Method 9 View Input Geometry l Input D gt EX Dike sand Dike sand 2 gt stiff clay EL Peat EJ Clayey sand a Pleistoceen sand X 105 000 v 37 750 Edit Current object None Figure 11 3 View Input window Geometry tab after importing geometry 5 Click Save as in the File menu enter Tutorial 4 as file name and click Save Model The calculation is carried out with the Spencer method as a user defined slip plane will be used 6 Open the Mode window from the Project menu Model Model Bishop f Spencer Fellenius Uplift an Uplift Spencer Bishop probabilistic random field Horizontal balance Reinforcements Geotextiles Nails Soll Resistance Default shear strength Cphi Stress tables Cu calculated Cu measured Cu gradient Pseudo values Measurements Reliability analysis Enable Default Input Values zone plot Enable Figure 11 4 Model window 7 Select the Spencer model 8 Click OK to confirm Importing material properties from an MGeobase database The layers geometry is already modeled however the material properties still need to be de fined Deltares 159 of 264 D GEO STABILITY User Manual The parameters from Table 11 1 were saved in an MGeobase database To import them the location
10. Figure 15 2 Model window Project Properties 10 On the menu bar click Project and then choose Properties to open the Project Properties window 11 Fill in Tutorial 8 for D GEO STABILITY gt and Zone Plot model gt for Title 1 and Title 2 respectively in the dentification tab 12 Click OK Zone Areas for Safety The six zone areas with a different required safety factor should be defined 13 Click Zone Areas for Safety in the Definitions menu to open the Zone Areas for Safety window 14 Enter the values given in Figure 15 3 in order to define the zone areas given in Figure 15 1 and the required safety factors given in Table 15 1 The Stability calculation is performed at the Right side as the river is situated at the left side of the dike 15 Click OK 198 of 264 Deltares Tutorial 8 Zone Plot Zone Areas for Safety zone and zone 3 Diketable height 0 1 Ims Left side of minimal road m 52 00 Start co ordinate restprofile Right side of minimal road m 155 00 Boundary of design level influence at x Required safety in zone 3a 10 93 Boundary of design level influence at y 3 Required safety in zone 3b 10 90 Required safety in zone 1a 7 Stability calculation at Required safety in zone 1b 7 Left side f Right side Required safety in zone a l l Safe overtopping condition restprofile Required safety in zone zb e01 m s C s01V m s Cancel Help Figure 15 3 Zone Areas for
11. 0 5Az tano The distance between the first fictitious interslice force and the sliding plane is zero Now calculating from the first to the last but one slice the distance can be calculated between the last but one interslice force and the sliding plane To keep the equilibrium of moments a fictitious rest moment Mest is required for the last slice Mrest can be calculated in the following way Mrest F COS n Xn A 0 5AP pptan 64 41 0 5Fr 4 sin Axi ja ZEB wo nt1On 1 Ss 1 16 38 For calculation of the rest moment a working line for the rest force Frest is defined by the horizontal line through point M The solution procedure of the Spencer method consists of the search for F and in such a way that both Frest 0 and Miest 0 The search for the correct values for F and is carried out by means of an iterative model using the following steps Choose starting values for F and Iterate formula 1 until Frest 0 F is adapted while is kept constant lterate formula 2 and 3 with the final values of the interslice forces from step 2 until Mrest 0 F is kept constant while is adapted With the values of F and that were gained by step 2 and 3 repeat the process from step 2 until Frest 0 and Mest 0 Iteration of Equation 16 36 step 2 is ended when the absolute value of rest force is less than c Iteration of Equation 16 37 and Equation 16 38 step 3 is ended when the absolute value of the
12. Fixed Calculated undrained cohesion Cu Refer to section 19 3 Calculated undrained strength for background information Shear strength model Cu calculated Y Ratio Cu Pc 1 0 22 POP kN m 10 00 Figure 4 23 Materials window Cu Calculated shear strength model Ratio Cu Pc The uniform ratio between the undrained strength s and the vertical pre consolidation stress P Values range typically between 0 18 and 0 26 POP The pre overburden pressure D GEO STABILITY uses this value to calcu late the pre consolidation stress P from the effective vertical stress Fo max o rer gh POP Ty The reference value of the vertical stress is determined from a reference level of the historic ground surface see section 4 4 5 Reference level for Ratio Cu Pc Fixed Measured undrained cohesion Cu Refer to section 19 2 Measured undrained strength for background information Shear strength model Cu measured Cu top kN me 6 00 Cu bottom kN me 8 00 Figure 4 24 Materials window Cu Measured shear strength model Cu top The apparent undrained strength s at the top of the layer Cu bottom The apparent undrained strength s at the bottom of the layer Fixed Undrained cohesion Cu Refer to section 19 3 Calculated undrained strength for background information Shear strength model Cu gradient Cu top kN me 6 00 Cu gradient kN mm 10 50 Figure 4 25 Materials window Cu gradient she
13. KM m 200 00 24 co ordinate at start m 2000 Y co ordinate at start rn CS i co ordinate at end rn 4800 Y co ordinate at end m 50 Reduction area m ES Cancel Help Figure 4 66 Geotextiles window 2 Add Insert a Delete Effective tensile The amount of tensile strength T s per unit width of geotextile kN m that strength is activated at common deformation levels X coordinate at The horizontal coordinate of the start of the section Start Y coordinate at The vertical coordinate of the start of the section Start X coordinate at The horizontal coordinate of the end of the section end Y coordinate at The vertical coordinate of the end of the section end Deltares 73 of 264 D GEO STABILITY User Manual Reduction area The required transmission length of the geotextile to enable the ten sile stress to grow to the full tensile strength If the length of a side near the intersection with a slip circle is less than the required length D GEO STABILITY will assume a tensile stress lower than the effective ten sile strength In that case D GEO STABILITY will use a linear dependency between tensile stress and side length For example a geotextile has a total length of 5 m of which 3 m are inside the slip plane The minimum length is therefore 2 m If this mini mum length is larger than or equal to the Reduction Area then the full tensile strength of the geotextile is taken into account
14. Log normal Distribution Normal Log normal 7 Cancel Help Figure 13 4 Probabilistic Defaults window It is possible to modify the probabilistic properties of each material individually by changing the numerical values In this tutorial the properties for Soft Clay shall be modified by changing the standard deviation of the friction angle from 3 to 5 14 Click Materials in the Soil menu 15 Select Soft Clay in the materials list 16 Deselect Use Probabilistic defaults 17 Enter lt 5 0 gt for the standard deviation of the friction angle Deltares 183 of 264 D GEO STABILITY User Manual Materials Maternal name Undetermined Add Insert Delete Rename Total unit weight Above phreatic level EN ree i 4 00 Below phreatic level kM rr 1 4 00 Shear strength model D efault E phi ha f Standard Shear strength input D efault Mean Use probabilistic defaults Advanced Shear strength parameters Mean Std dev Distribution Cohesion c kM n 18 00 14 1 4 2 00 Log normal Friction angle phi deg 20 00 i 1 75 5 00 Log normal Pl pare pressure parameters Std dev Distribution Hydraulic pressure kM n 10 50 Log normal Cancel Help Figure 13 5 Materials window for Standard input It is also possible to describe the materials properties in more detail i e provide probabilistic information on the use of cohesi
15. UPL upoc Utemp load Uquake 18 5 Deltares 231 of 264 D GEO STABILITY User Manual where UPL is the pore pressure derived from the PL lines see Equation 18 1 in sec tion 18 2 UDOC is the pore excess under pressure derived from the degree of consolidation see Equation 18 3 in section 18 3 Utemp load S the extra pore pressure from temporary distributed loads see Equation 18 4 Uquake is the extra pore pressure due to vertical quake see Equation 17 6 in sec tion 17 3 2 The pore pressure derived from the PL lines represents up the situation without any loads being applied while the extra pore pressures due to the consolidation process upoc and temporary loads Utemp loaa are the result of the extra loading of soils with a low permeability D GEO STABILITY determines the effective stress at depth z using o z a z u z 18 6 where u is the total pore pressure Equation 18 5 and o z is the total stress at depth z O z Osoil z za Ady z Ofree water z 18 7 with k Osoi 2 Y Y xh i l O free water z ores y z D 0 where h is the thickness of layer 2 k is the number of layers until depth z along the considered vertical Zphreaic IS the level of the phreatic line see section 18 1 f is the unit weight of soil layer 4 in kN m Osoi Z is the stress due to soil weight Owater 2 is the stress due free water above the soil surface Ag z is the increase of the total
16. is that this thrust line can have a discontinuity In such a case the result of Spencer s limit equilibrium method can be questioned Uncontrained slip plane Tutorial 4c D GEO STABILITY offers the unique possibility to search for the slip plane with the least resis tance without presupposing the shape of the slip plane In the previous section section 11 4 two slip planes are defined and a grid based routine combines all the possible failure surfaces As noted a higher number of transversal points will result in an exponential increase in slip planes to be evaluated and thereby also in the calculation time The genetic algorithm calculation option is so efficient that it can find a slip plane between these boundaries 55 Click Save as in the File menu and save this tutorial as lt Tutorial 4c gt 56 Click Save Deltares 169 of 264 D GEO STABILITY User Manual Note Too many points on a slip plane can decrease the smoothness of a slip plane and therefore increase the resulting safety factor In general 10 12 points along the plane are sufficient to find an uncontrained slip plane 11 5 1 Calculation and Results 57 Click Start in the Calculation menu 58 Select Genetic algorithm Start Search methad C Grid f Genetic algorithm Display Report Me Graphic indicator le Short report Long report OF Cancel Help Figure 11 20 Start window Tutorial 4c 59 Click the Options button to open the
17. le Probabilistic Cancel Help Figure 5 2 Start window Grid method Move grid Activate this check box if D GEO STABILITY should move the grid in the direction of the minimum safety factor Deactivate if D GEO STABILITY should only calculate the minimum safety factor with the initial grid Graphic indicator Activate if D GEO STABILITY should graphically display the progress of the automatic slip circle search Report type Select the report type The long report will contain all available re sults The short report will contain only key data Calculation type Only in combination with reliability analysis section 4 1 1 Select the calculation type a mean value analysis a design value analysis or a probabilistic design with random parameter values 5 2 2 Genetic Algorithm based calculation Start Search method Move grid Options Display Report w Graphic indicator le Short report Long report Cancel Help Figure 5 3 Start window Genetic algorithm method A genetic algorithm is an advanced optimization method that is particularly good in finding a solution in a large and complex search space It searches the same space as the calcula tion grid without analyzing every possible grid point With the right options is it much more efficient The Genetic Algorithm is only implemented in combination with the following limit equilibrium methods Bishop Spencer Fellenius Uplift Van
18. 1 7 as piezometric level for all the layers Figure 8 19 60 Click OK PL lines per Layer EN Layer PL line PL line Number at top at botto H al 1 Mt 1 m 1 1 Figure 8 19 PL lines per Layer window See section PL lines per Layer section 4 3 13 for a detailed description of this window 132 of 264 Deltares Tutorial 1 Dike reinforced with berm 8 4 4 Check Geometry It is possible to check whether the defined geometry has any errors 61 Click Check geometry in the Geometry menu At this point an information window indi cating that the entered geometry is correct should appear Figure 8 20 Information mm o The geometry has been tested and is ok Figure 8 20 Information window 62 Click OK See section 4 3 14 Check Geometry for a detailed description of this window 8 5 Soil In the Soil menu it is possible to modify properties of the soil layers that were created earlier section 8 2 4 to be in accordance with Table 8 1 63 Choose Materials from the Soil menu to open the Materials window 64 Select Dense Sand in the material list Click Rename and change Dense Sand into lt Berm Sand Materials ES Total unit weight METETE Above pesao level ken 14 00 Medium Clay Below phreatic level kN 4rr 1 4 00 Stiff Clay F Shear strength model Default E phi Cohesion c kN rre 18 00 Undetermined Friction angle phi deg 20 00 Add Insert a Delete Rename
19. 15 000 Ytop m 8 000 aight m 23000 bottom m 6 000 Humber e o Humber B Tangent line Fixed point top m 1 500 Use fixed point Y bottem m 4 500 0 000 Humber E 0 000 Cancel Help Figure 9 6 Slip Circle Definition window 9 6 Calculation and Results 26 To perform the calculation select the Start option from the Calculation menu and click OK 27 Select the Stresses option from the Results menu to open the Critical Circle window Fig ure 9 7 In this window the slip circle with the lowest safety factor is shown The safety factor is relatively low 0 84 9 Critical Circle GEA Edit o Materials BO EU Berm Sand erc __ Soft Clay Tools z C Peat 5 j EX Sand Mode Bos TUU Uu Uy Xm 25 29 m Radius 18 21 m Ym 16 29 m Safety 0 84 X 33 313 ie 22943 Edit Figure 9 7 Critical Circle window It is common for a calculation which incorporates the undrained shear strength properties of a soil type to result in a lower safety factor than for soil with a c phi shear strength model To compare the results for calculations using an undrained sheer strength and c phi relation change the sheer strength model in the Materials option in the Soil menu Run the calculation again and compare the results When a c phi shear strength model is used for Soft Clay the safety factor will be 1 38 Deltares 151 of 264 9 7 D GEO STABILITY User Manu
20. 33 Help menu 2 2 2 2 252525 25 5 5 3 3 1 Error Messages ds MOUA ea ewe ee eee 3 R9 909 as 3 3 3 Deltares Systems Website dae UNO 2 c9 ee ee oR 8 EX ox REOR Be Weg 3 3 5 JAboutD GEO STABILITY 4 m9 o9 o9 Pie S ROROR Bie edo 4 Input 4 1 Projectmenu uoo o DE odo Deo E Ode uen EO de xoc o cR Oo He oO Deltares Contents D GEO STABILITY User Manual 4 2 4 3 4 4 4 5 4 6 ALL NON ssa raserer aos ee wee ee ee hee eeee 29 4 1 2 Probabilistic Defaults 32 4 1 3 Project Properties 5250s OE MMe o RD EO 4 ee ee 33 4 1 4 View Input File 38 SOl MENU gt a i s a carea nisi RA o3 de x o ROO Xo X 38 4 2 1 Sigma Tau Curves a a a a 39 4 2 1 1 Sigma Tau Curves for deterministic design 39 4 2 1 2 Sigma Tau Curves for Reliability analysis 40 4 2 1 3 Sigma Tau Curves for Pseudo values Shear strength model 41 4 2 2 Bond Stress Diagrams 42 42 3 Materials o Mb 43 4 2 3 1 Materials Input of fixed parameters 43 4 2 3 2 Materials Import from Database 46 4 2 3 Materials SoilGroups 47 4 2 3 4 Materials Reliability Analysis 48 4 2 3 5 Materials Bishop probabilistic random field method 54 42 36 Materials Nails
21. 4 ius H aAa 19 na 18 A 20 IRR 25 prr 29 A 5 DEREN 40 DS 145 CA 59 O 55 A eo CN es RRR H naaa ii NS e m Materials Mn how Y 7 Berm Sand Y 3 E Soft Clay am G E C Peat DE m EX Sand 7 Tools A b EEE X 52 750 Y 8 000 Edit Current object None Figure 13 9 View Input window Geometry tab PL lines per Layer In this tutorial the piezometric level of all the layers coincides with the phreatic line which is the upper line in Figure 13 1 Water In the geometry three different piezometric level lines are drawn In the design case the upper line functions as the phreatic line The second line has been added to be incorporated as a mean high water level in this probabilistic calculation The lower line will be incorporated as a mean low water level To define how the water levels are to be incorporated do the following 34 Click External water levels in the Water menu 35 Mark the Use water data check box First a design level must be set for the calculation 36 In the Water level sub window enter 4 0 m gt as Design level and 0 3 m gt as Decimate height 37 Set the level of exceeding to 1 2000 This means that this water level is exceeded once every 2000 years In order to describe the first water level do the following 38 Click Rename and change the name of the current water level to lt MHW gt Mean High Water 39 In the PL lines sub window the Phreatic line
22. 88421 45975 579 36107 73051 466 22646 44771 156 39300 76036 B43 59375 B7B46 669 934993 83458 5956 69256 49506 527 32578 07802 431 92230 54068 5869 38007 77578 474 24437 48414 154 04207 B2243 B77 63575 31243 703 359108 00595 826 73693 65354 amp amp I 6 amp i amp 6 6 6 6 6 a 6 6 6 6 6 6 6 6 6 Ei 6 6 6 Fe T T Pe 7 7 Es Es Fe Pe Pa de Ri Ri Ri Ga Ri Ri Ri Ri Ri Ri Ri Da PRO Ra M3 Ra M3 Ma BO to M Ma Ri Ri Ri Ri Ra Ga Ri Ri Ri Ri Ri hi Ri Qi i i i i i i tO to oO Ba Ri Ri G Ga Ga Ha da Ri BI Ri Gas W Gs da da Ai BI Ri C GO C ds da Ai Ri RI DO G w d i i i i i ds oO d BB G abs da yy ee RY Ri da Ca ds am Ch i i i Figure 6 2 Report window intermediate results 94 of 264 Deltares View Results Computation of index of reliability including the effect of randomness of extreme waterlevels Reliability index Design value high water lt Humber of iterations alfas Fluctuation Uncertainty fluctuation Uncertainty Correlation Uncertainty Uncertainty cohesion average value cohesion lt tan phi average value tani phi lt cohesion and tan phi excess pore pressure freatic line Model uncertainty Uncertainty water level Figure 6 3 Report window final results The short report gives the following output of the final analysis results see Figure 6 3 Reliability index
23. 95 of 264 D GEO STABILITY User Manual Coordinate 37 500 m Materials Figure 6 4 Stresses in Geometry window 6 3 Stresses 6 3 1 Critical Circle Fellenius and Bishop On the menu bar click Results and then select the Stresses option to open the Critical Circle window which gives access to various graphical representations of the calculated results for Fellenius or Bishop method Key information like the safety factor and the probability of failure are printed in the status panel at the bottom EA treet BE LE 4 Xm 46 43 m Radius 11 36 m Ym 7 71 m Safety 1 10 X 54 108 Y 12 257 Edit Figure 6 5 Critical Circle window Click on the following buttons to view The critical slip circle with the initial and final position of the grid D Tre distribution of the vertical total stress 96 of 264 Deltares View Results o The distribution of the vertical effective stress t The distribution of the shear stress along the slip plane The hydrostatic pore pressure component along the slip plane from the phreatic Uu line definition The hydraulic piezometric pore pressure component along the slip plane from Lu the piezometric lines definition or the MSeep pore pressures The excess pore pressure component along the slip plane caused by the speci Uj fied degrees of consolidation by addition of different layers and loads The total pore pressure along the slip p
24. Bishop and Fellenius Spencer module This tutorial is presented in the files Tutorial 4a sti to Tutorial 4c sti Introduction to the case In the soil structure geometry of this tutorial Figure 11 1 two different piezometric levels are assigned to the different layers Moreover some of the layers have not completely consoli dated to model this it is possible to input a degree of consolidation for each layer In addition loads are applied on the dike To see what effect this will have on the stability of the dike a calculation using the Spencer method will be carried out One might use this method when there is reason to believe that the slip plane might have a preferred shape Figure 11 1 Dike with different water levels at either side Tutorial 4 The relevant values of the soil types used in this tutorial are given in Table 11 1 Deltares 157 of 264 11 2 1 D GEO STABILITY User Manual Table 11 1 Soil properties Tutorial 4 Cohesion Friction angle Unsaturated Saturated unit weight unit weight kN m kN m kN m Demi CA m E 5 say 30 je 120 8 Pa 8 i M i6 Pleistocenesand 0 27 18 For this project three different calculation are performed Tutorial 4a uses one defined slip plane Tutorial 4b uses two defined slip planes to generate a multitude of slip planes presup posing the shape of the slip plane i e grid based rou
25. Choose Start in the Calculation menu to open the Calculation window 18 Click OK To view the results Field Method 19 Choose Stresses from the Results menu The Critical Circle window will appear Fig ure 14 4 P Critical Circle gt Design level 4 00 m yl Xm 52 14 m Radius 15 64 m Ym 12 00 m Safety 1 48 beta 0 02 probability of failure 4 90E 01 X 57 614 Y 8 107 E dit Figure 14 4 Critical Circle window The results of the Bishop Random Field method measurements for the critical slip plane and probability of failure are given for each of the three described water levels MLW MHW and design level using the drop down menu at the top of the Critical Circle window Deltares 195 of 264 D GEO STABILITY User Manual 14 5 Conclusion The Bishop Random Field method is capable of performing a probabilistic slope analysis It can incorporate stochastic descriptions of soil parameters and external water levels lt calculates the probability of failure according to a required safety factor 196 of 264 Deltares 15 Tutorial 8 Zone Plot The case from Tutorial 1 chapter 8 is used in this tutorial to determine the safety factor of the dike using the Zone Plot model The dike body is divided into six parts called 1a 1b 2a 2b 3a and 3b with a different required safety factor The objective of this tutorial is To learn how to perform a calculation using the Zone Plot
26. D GEO STABILITY s graphical interface requires just a short training period allowing users to focus their skill di rectly on the input of sound geotechnical data and the subsequent evaluation of the calculated stability of a slope D GEO STABILITY comes as a standard module that can be extended with other modules to fit more advanced applications Spencer model Uplift Van model Deltares 1 of 264 D GEO STABILITY User Manual Reliability model Probabilistic random field model 1 3 Features in standard module This section contains an overview of the features in D GEO STABILITY for the calculation of slope stability For more information on this topic see the Reference and Background sections of this manual 1 3 1 Soil modeling Multiple layers The two dimensional soil structure can be composed of several soil layers with an arbi trary shape and orientation The deep soil layer is assumed to be infinitely thick Each layer is connected to a certain soil type It is possible to combine layers with different material models Geotextiles It is possible to model geotextiles with arbitrary inclination The stability of a slope will increase if a slip plane intersects with a geotextile Nails It is possible to model nails with arbitrary inclination The resisting moment of the soil will increase due to the nails Drained and undrained behavior Soil parameters are defined per soil type Besides input of a cohesion c and i
27. Pa Peat on S 5s EX Sand D e f EX 4 Tools A zB T z E Bi E D US n Ko if Muu do AAA X 66 000 Y 6 250 Edit Current object None Figure 8 8 View Input window 18 Click Save as in the File menu 19 Enter Tutorial 1a as file name 20 Click Save Deltares 125 of 264 8 3 8 3 1 8 3 2 D GEO STABILITY User Manual Project Model At this point the calculation model is to be set In this tutorial the minimum safety factor for the dike structure must be determined This can be done by assessing the stability of the dike via one of its possible failure mechanisms namely a slip circle The Bishop method performs calculations on such a slip circle therefore the Bishop model is used in this tutorial Later in Definitions section 8 6 it will be described how D GEO STABILITY uses the Bishop method to determine the minimum safety factor for the soil structure 21 Choose Model from the Project menu to open the Model window Figure 8 9 22 23 24 25 26 Default shear strength Bishop C phi f Spencer f Stress tables f Fellerius Cy calculated f Uplift Yan Cy measured f Uplitt Spencer f Cy gradient f Bishop probabilistic random field f Pseudo values Horizontal balance Reinforcements Reliability analysis Geotextiles Enable Nails Zone plot Enable Cancel Help Figure 8 9 Model window Sel
28. T au ultimate EM re 100 00 E m E m E 3 3 m E Input Bond Stress Diagram Alg Zand 0 30 60 0 40 0 20 0 0 0 0 0 50 0 Sigma ultimate kIM rm 1 0 1500 2000 OF Cancel Help Figure 4 19 Bond Stress Diagrams window with imported data On the menu bar click Soil and then select Materials in order to open the Materials window in which material parameters can be imported or entered The content of this window depends on the selected model 4 2 3 Materials 4 2 3 1 Materials Input of fixed parameters section 4 2 3 1 Input of fixed parameters for traditional deterministic design section 4 2 3 2 Import from a material library section 4 2 3 3 Input of parameter distributions for reliability based design section 4 2 3 4 Input of parameters for pseudo values shear strength model section 4 2 3 5 Input of parameters for Bishop probabilistic random field method section 4 2 3 6 Input of parameters for the soil nails interface The input of fixed parameters for traditional deterministic design is described in this section Deltares 43 of 264 D GEO STABILITY User Manual Materials Total unit weight Sena mamie Above pro level kien 14 00 Medium Clay Below phreatic level kN rr 1 4 00 Stiff Clay F Shear strength model Default E phi Cohesion c EN frre 18 00 Undetermined Friction angle phi deg 20 00 Add Insert Delete Rename
29. The basic geometry of this tutorial Figure 13 1 is based on Tutorial 1b section 8 9 17 5m 6 0m 10m 8m 3m Design level 50m Figure 13 1 Geometry overview Tutorial 6 Click Open in the File menu Select Tutorial 1b Click Open Click Save as in the File menu and save this tutorial as Tutorial 6 Click Save 0O AOON Deltares 181 of 264 D GEO STABILITY User Manual 13 2 Model 6 Click the Model option in the Project menu 7 Make sure the Bishop method is selected 8 Mark the Enable Reliability analysis check box as a probabilistic calculation will be per formed Model Model Default shear strength le Bishop i phi Spencer Stress tables Fellenius Cu calculated Uplift van Cu measured Uplift Spencer Cu gradient Bishop probabilistic random field Pseudo values f Horizontal balance Reinforcements Reliability analysis Geotextiles Default Input Values Nails Zone plot E Cancel Help Figure 13 2 Model window 9 Click on the Default Input Values button to open the Default Input Values window and choose mean as input values Figure 13 3 Default Input Values f Design Cancel Help Figure 13 3 Default Input Values window 10 Click OK to close the Default Inout Values window 11 Click OK to close the Model window 13 3 Probabilistic Defaults To perform a probabilistic calculation D GEO STABILITY makes
30. The default is set to 100 The distribution is set to O degrees Calculation using one defined slip plane Tutorial 4a Slipe Plane To perform a calculation with the Spencer model a slip plane has to be created 33 Select the nput tab in the View Input window 34 Create a slip plane by clicking the Add slip plane button 164 of 264 Deltares 11 3 2 Tutorial 4 The Spencer Method D View Input Edit na X 84 750 35 x n Geometry Input eJ y E Le m Materials EU Dike sand E Dike sand 2 EJ Stiff clay T Peat E Clayey sand __ Pleistoceen sand 30 25 E 155 10 a io Current object Spencer Slipplane n2 en e 25 000 Edit Figure 11 12 View Input window Input tab Tutorial 4a Draw the slip plane by placing ten points from left to right in the dike body Figure 11 12 suggests a shape for the slip plane 36 manually 37 38 Click OK Click Slip Plane in the Definitions menu to view the properties of the slip plane just created Modify the X and Y coordinates of the slip plane to be in accordance with the values of Figure 11 13 Cancel Help Figure 11 13 Slip Plane Definition window Tutorial 4a As only one slip plane is inputted D GEO STABILITY will calculate only one safety factor for this slip plane D GEO STABILITY allows the calculation of either one or a multitude of sli
31. The geometry has been tested and is ok but one or more layers have no PL lines Figure 4 55 Warning window on confirmation of a valid geometry 4 4 Definitions menu 4 4 1 The Definitions menu can be used to enter definitions slip plane geometry specifications Slip Plane Definition To open the input window for slip plane definition click the button at the left of the View Input window section 2 2 3 or use the menu bar section 2 2 1 open the Definitions menu and choose Slip Plane Depending on the selected model in the Model window section 4 1 1 the content of the win dow will be different Refer to section 4 4 1 1 for Bishop and Fellenius models 65 of 264 D GEO STABILITY User Manual Refer to section 4 4 1 2 for Uplift Van and Uplift Soencer models Refer to section 4 4 1 3 for Soencer model 4 4 1 1 Slip Circle Definition Bishop or Fellenius The following applies when the Bishop or Fellenius method is selected section 4 1 1 D GEO STABILITY determines the critical slip circle in an iterative way The trials that D GEO STABILITY performs are based on a grid of center points and a set of horizontal tangent lines Both the grid and the tangent lines can move towards the direction with the lowest safety factor during the calculation process In the input window the initial location of the grid and the initial location of the horizontal trial tangent lines are supplied In addition it is also poss
32. This window shows a diagram of the Safety factor Model factor vs the Entry point active circle i e X coordinate for the calculated slip circles of each zone Mark and unmark the available check boxes at the right side of the window to show the corresponding zone The horizontal black lines in the diagram correspond to the required safety factors of each zone as defined in the Zone Areas for Safety window section 15 3 Any result is available for Zone 1b which means that any circle pass through this zone For zone 1a many points are situated below the required safety factor line which means they are not acceptable See section 6 5 Safety Factor per Zone for a detailed description of this window Stresses per Zone To view the graphical representation of the zone areas do the following 24 Click the Stresses per Zone option in the Results menu to open the Critical Circle window Figure 15 6 25 Click the Previous zone and Next zone icons to view various calculated results for each Zone The bold red line represents the rest profile The vertical and horizontal dotted black lines represent the boundaries of the design level influence respectively at X and Y The two inclined dotted black lines at the right side of the window represent the limits of the minimal road influence Information like the radius and center coordinates of the critical circle and the 200 of 264 Deltares Tutorial 8 Zone Plot safety factor are prin
33. User Manual from our website www deltaressystems com 260 of 264 Deltares Bibliography Program UTEXAS3 URL http www wass entpe fr steph engstef case engcomp htm July 1993 Soil Nailing Recommendations 1991 for Designing Calculating Constructing and Inspecting Earth Support Systems Using Soil Nailing English Translation Tech rep Recommendations CLOUTERRE 1991 Alonso E 1976 Risk Analysis of Slopes and its Application to Canadian Sensitive Clays Geotechnique vol 26 no 3 American Petroleum Institute Washington D 1984 Recommended practice for planning designing and constructing fixed offshore platforms Calle E O F 1985 Probabilistic Approach of Stability of Earth Slopes Proc XI th ICSMFE San Francisco Calle E O F 1990 PROSTAB A Computer Model for Probabilistic Analysis of Stability of Slopes GeoDelft report CO 266484 32 in Dutch Calle E O F 2000 Aaanpassing MPROSTAB GeoDelft report CO 395380 04 in Dutch CUR 1992 Publicatie 162 Construeren met grond Grondconstructies op en in weinig draagkrachtige en sterk samendrukbare ondergrond Civieltechnischcentrum Uitvoering en Regelgeving Dutch report SE 52029 2 in February 2000 Development of Uplift Stability Theory Tech rep GeoDelft Geodelft Dutch report SE 703234 02 in January 1992 Spanningsafhankelijk rekenen in MStab Tech rep GeoDelft NEN 1997 NEN 6740 Du
34. Y bottom The initial vertical coordinate of the lowest tangent line of a trial slip circle Number The number of tangent lines in vertical direction Automatic at Mark this check box to define tangent lines at the boundaries between the boundary different layers 4 4 1 3 Slip Plane Definition Spencer The following applies only when the Spencer method is selected section 4 1 1 P Slip Plane Definition W Generate slip planes Transversal grid points E Generated planes 243 23 750 23 750 30 250 27 000 36 999 34 454 Cancel Help Figure 4 58 Slip Plane Definition window Spencer method It is possible to generate a single slip plane by entering X and Y coordinates into the table This is possible when the Generate slip planes option in this window is not selected The table will then only contain two columns It is also possible to input a range of slip planes by entering the X and Y coordinates of two slip planes in the table The slip planes used in the calculation will all lie between these two planes This is possible when the Generate slip planes option is selected The table contains four columns in this case Both planes should contain the same number of points Therefore empty input fields are not allowed The number of slip planes that are generated depends on the number entered as the Transver sal grid points parameter 68 of 264 Deltares Input If the parameter Transversal grid points is 1 only the f
35. ZR x Py x Pry JP TL P x PX 20454 Pi ejr X Pi x Ph where Pjgoba is the global pseudo characteristic factor for layer 7 Fii is the pseudo characteristic factor of the soil group containing layers 7 and k P P is the local pseudo characteristic factors of layers7 and k see Equation 19 6 238 of 264 Deltares 20 20 1 20 2 Reliability analysis Supported methods Commonly used design standards like the Eurocode and the Dutch NEN standard prescribe to apply reliability based approach for both structural and geotechnical design For this purpose the standards supply two options o Design value approach semi probabilistic level IIl In this approach calculations are made with combinations of unfavorable values of input parameters for resistance and loads The unfavorable values are called design values They are determined by ap plying a partial factor on the unfavorable characteristic value commonly defined by a confidence limit of 95 The characteristic value of parameter follows from a stochastic distribution usually defined by mean and standard deviation where the standard de viation quantifies the uncertainty In D GEO STABILITY calculations the calculated safety factor must be larger than the required value Fs gt Frequired Probabilistic approach This is an analysis with free variations of stochastically dis tributed input parameters defined by mean and standard deviation A level ll analysis with FOR
36. min CETE Zibutt m If the soil within the slip plane height is dry then H 0 Utop is the hydrostatic pore pressure at the top of the saturated soil level Utop Foes min Zonreste Ztop X Yw Uh bot is the hydrostatic pore pressure at level Ziangent Ubot Z uestis Zottom X Yw Ziop is the top level of the vertical layer boundary Zbotom s the bottom level of the vertical layer boundary Refer to section 1 8 for the definitions of the other symbols 206 of 264 Deltares 16 2 1 3 16 2 2 16 2 2 1 Method of slices Driving load moment The part of the uniform loads and the line loads located within the confines of a slip circle creates a moment Mb vag around the slip circle center point Toads lines Mbojo 9 Fy x Aw x AX Y Fix AX 16 7 j l 1 with AX _ X B max CX yen A basins min Cert Kegs AX E X o max CX den Xi t min A iani Xi Aw min ich Nenda Max CX aen Xp where F is the magnitude of uniform load number 7 in KN m Fi is the magnitude of line load number in KN m Mies is the total number of lines loads loads is the total number of uniform loads Xbegn is the X coordinate o f the starting point of load 7 Xena is the X coordinate of the ending point of load 7 X is the X coordinate of line load X lett is the X coordinate of the left side of slice 1 i e entry point of the slip circle AX n rigt IS the X coordinate of the right side of slice n i e e
37. robust easy to use modelling suite Deltares offers high quality software services to consultancy firms governmental organizations universities and Documenten research institutes worldwide using these software products To obtain the support of your convenience please contact sales deltaressystems nl For those with M Bou D Geo o cH Maintenance amp Support in place please contact support deltaressystems nl da D Geo Stability Manual 3 Known issues da D GeoStability Verification Report E1 Unsolved Uplift Van method can lead to incorrect safety factor if the water pressures along the da Release notes D Geo Stability 3 horizontal part is not the same For Uplift Van calculation the horizontal water forces acting on the compressed area i e at the end of the active circle and at the start of the passive circle are not taken into account but they are taken into account for the calculation of the water moment This Figure 1 1 Deltares Systems website www deltaressystems com If the solution cannot be found there then the problem description can be e mailed preferred or faxed to the Deltares Systems Support team When sending a problem description please add a full description of the working environment To do this conveniently Open the program If possible open a project that can illustrate the question Choose the Support option in the Help menu The System Info tab contains all relevant information about t
38. see Equation 16 3 Cfw is the free water factor as defined in the Earthquake window in section 4 7 3 Deltares 227 of 264 D GEO STABILITY User Manual 17 4 Tree on Slope The effect of the wind in the trees is equivalent to the effect of two uniform loads at both sides of the application point one positive the other one negative Figure 17 3 W Figure 17 3 Representation of the effect of wind on trees The magnitude of the equivalent uniform load q is P wing xh w 2 17 8 where Fwing is the magnitude of the wind in kN m h is the vertical distance slope wind in m W is the horizontal width of the root zone in m The increase of stress is the sum of the stress due to the equivalent load respectively at the left and at the right q X Ww Net SSS SS 17 9 id EU 2 Zina h p sw 2 Z4 x tan qx w Grant ML N 17 10 TEM wF 2 Zwind m h ly 2 Zy4 x tan where Zwing s the vertical co ordinate of the application point of the wind in m Zu is the vertical co ordinate at the bottom of slice in m The driving moment due to tree on slope is therefore Mag m L id X Zwind Z dicis 17 11 228 of 264 Deltares 18 18 1 18 2 Pore pressures Phreatic line The phreatic line or groundwater level is used to mark the border between dry and wet soil The phreatic line is treated as if it was a PL line and can also be used as such The PL line acting as
39. v Cancel Help Figure 4 20 Materials window for fixed value input Total Unit The unit weight of the unsaturated soil above the phreatic line Gamma Weight Yunsat and the weight of the saturated soil below the phreatic line Ysat Shear strength Use one of the following shear strength models either by default as model defined in section 4 1 1 or by specific selection see below C phi Stress tables Cu calculated Cu measured or Cu gradient _ Add Click this button to add a new material at the end of the existing list Insert Click this button to insert a new material after the selected material Delete Click this button to delete the selected material Rename Click this button to rename the material Fixed Cohesion and friction C phi Refer to section 19 1 and section 16 2 2 1 1 for background information Shear strength model Ic phi Cohesion c kN ne 9 00 Friction angle phi deg 20 00 Figure 4 21 Materials window C phi shear strength model Cohesion The cohesion c Friction Angle The internal friction angle y Fixed Stress table Sigma Tau Refer to section 19 1 Stress tables for background information 44 of 264 Deltares Input Shear strength model Stress tables v Stress table Btw AL Basisveen Figure 4 22 Materials window Stress Tables shear strength model Stress table Select a previously defined Sigma Tau curve section 4 2 1 from the list
40. 0 1 fms Left side of minimal road rn ETS Start co ordinate restprofile Fight side of minimal road m EXT Boundary of design level influence at x Required safety in zone Ja DN Boundary of design level influence at y J Required safety in zone 3b RIEN Required safety in zone la Stability calculation at Heguired safety in zone 1b Left side f Right side Required safety in zone za l l Safe overtopping condition restprofile Required safety in zone zb f lt 0 1 m COR lms Cancel Help Figure 4 63 Zone Areas for Safety window Dike table height Level Z coordinate of the dike table m 0 1 m s Deltares 71 of 264 D GEO STABILITY User Manual Start x coordinate rest profile Boundary of design level influence at x Boundary of design level influence at y Required safety in zone 1a Required safety in zone 1b Required safety in zone 2a Required safety in zone 2b Left side minimal road Right side minimal road Required safety in zone 3a Required safety in zone 3b Stability calculation at Safe overtopping con dition restprofile River X coordinate of the starting point of the rest profile m Vertical boundary of the design high water level m Horizontal boundary of the design high water level m Required safety factor in zone 1a of the dike Hequired safety factor in zone 1b of the dike Required safety factor in zone 2a of the dike Hequired safety factor in zone 2b
41. 1 D GEO STABILITY User Manual circle and by an additional contribution from geotextiles Fellenius defines the safety factor by simply using the ratio between the driving moments and the ultimate resistance moment Bishop defines the safety by the reduction factor that can be applied to cohesion and the tangent of the friction This means that only with Bishop s method the equilibrium of vertical forces is preserved Therefore Bishop s method is preferred The equilibrium evaluation is based on the summation of the influence of the all slices The equilibrium evaluation of a slice includes the forces and pressures in Figure 16 2 Wi Ni 1 Ali Ax cos0 Figure 16 2 Equilibrium for one slice The next section describes how the different moments are calculated for a slice Driving moments Driving soil moment The driving soil moment Mp soi is the moment caused by the mass of the soil within the slip circle around its center Mob soil y Gy X op Lo 16 1 i l with ki j l 204 of 264 Deltares 16 2 1 2 Method of slices G is the weight of the soil in slice 2 see Figure 16 2 in kN m h is the thickness of layer 7 in slice 7 ki is the number of layers along slice 2 n is the number of slices Yj is the unit weight of soil layer 7 in slice in KN m Refer to section 1 8 for the definition of the other symbols The unit kNm m indicates the moment per 1 meter of the cross section perpendi
42. 1 2010 10 20 AM STIFile P Tutorial 4b 10 1 2010 10 20 AM STI File P Tutorial 4c 10 1 2010 10 20 AM STI File P Tutorial 5 10 1 2010 10 20 AM STI File P Tutorial 6 1 14 2011 12 59PM STI File P Tutorial 7 10 1 2010 10 20 AM STI File F Tutorial 8 10 1 2010 10 20 AM STI File Tutorial 1 a Deltares files geo sli sti dri sei Figure 4 44 Import Geometry From window Import geometry from database To be able to import a geometry from a database this option has to be provided with the purchased version of D GEO STABILITY To import a geometry from a database click mport from Database in the Geometry menu The Select Geometry dialog will appear Again the imported geometry will replace the current one and will be displayed in the View Input Geometry window Note This option is only available when the correct database directory has been specified using the Locations tab in the Program Options menu see section 4 2 3 For more informa tion on MGeobase visit www deltaressystems com 58 of 264 Deltares Input 4 3 5 Export This option displays a standard Save As dialog that enables the user to choose a directory and a file name and format in which to save the current geometry file The file will be saved in the standard geometry format for the Deltares Systems Geo tools geo Files in this format can be used in a multitude of Deltares Systems geo programs such as D
43. 1250 Decimate height m 10 30 Pllinez Water data name Mw Phreatic line number 3 Level Fl line Pine at tap at top 5 EN EE SES E EE Add Inizert al gt Delete Rename Copy from Geometry Cancel Help Figure 4 73 External Water Levels window In the top part of the External Water Levels window the design level itself is entered together with the exceeding frequency for that same level D GEO STABILITY expects that the associated hydraulic field for this level via the PL ines per layer option from the Geometry menu is already defined The lower part of the External Water Levels window enables the user to define a maximum of four additional levels and associated fields It is possible to add modify or delete the names of fields at the left hand side At the right hand side the external level can be entered together with the associated PL lines at the edges of all soil layers A value of 99 yields a linear interpolation between the PL lines at the outside of the cluster The Copy from Geometry button allows the user to define a new field by modification of a copy of the design level field A further description of nontrivial input fields is given below Design level The design level design corresponding to the hydraulic field that has been specified via the PL lines per layer option from the Geometry menu See section 20 4 5 Equation 20 23 Decimate height The increase in the external water
44. 1a llle 201 16 1 Slip plane including method of slices 203 16 2 Equilibrium for one slice 204 16 3 Horizontal water pressures due to free water acting on the side of a slice in case of vertical layer boundary e e 206 Deltares XV D GEO STABILITY User Manual Xvi 16 4 Resisting contribution by geotextiles 208 16 5 Resisting contribution by nails a 209 16 6 Representation of the four criteria in the Fn Fp diagram to determine Fi 210 16 7 Representation of the Tresca s criterion by Mohrscircle 213 16 8 Relation angle a Shear Stress for Gmin ID 216 16 9 Uplift failure mechanism a a a a oll lll 217 16 10 Van Uplift Stability derivation lr rn 217 16 11 Interslice forces according to Spencer method 219 Mel Une LOO ne eee a aa oe aa eae ea UT 224 172 VON Load a dox Eb oe eee Bee eee ee a a S s 225 17 3 Representation of the effect of wind on trees 228 181 PL lines per layer Ma LS 230 19 1 Example ofo 7 curve P gt 234 19 2 Stress induced anisotropy l l lll ln 235 19 3 Reference level and stress induced anisotropy 236 20 1 Limit Surface and Limit State Function 244 20 2 Linear interpolation between the conditi
45. 4 3 The first thing to do when creating new geometry is to set the model limits This is possible by selecting and then dragging the limits to their proper place one by one It is also possible to select a limit and edit its value by clicking the right hand mouse button after selecting the limit and then choosing the Properties option in the pop up menu The property window belonging to the selected limit is displayed Figure 7 9 enabling to define the new X coordinate for this limit Right Limit x Limit at right side m 75 000 Cancel Figure 7 9 Right Limit window Draw layout It is possible to use the Add single line s Add polyline s and Add point s to boundary PL line buttons to draw the layout of the geometry See section 2 2 3 for more information s on how using those buttons Pay ER ra ad Add single line s and Add polyline s Each poly line is displayed as a solid blue line and each point as a small black rectangle Figure 7 10 Deltares 111 of 264 D GEO STABILITY User Manual Figure 7 10 Representation of a polyline The position of the different points of a poly line can be modified by dragging the points as explained in section 7 5 4 or by editing the poly line This is done by clicking the right hand mouse button after selecting the poly line and then choosing the Properties option in the pop up menu section 7 5 3 The underlying grid helps the user to add and edit poly lines
46. 8 8 more understandable 29 Select the View Input tab Figure 8 11 to change the settings of the View Input window 30 Mark the Points check box of the Labels sub window in order to display the points number 31 In the Layers sub window select As material names to display the material name of the different layers 32 In the Grid sub window enter a Grid distance of 0 25 m instead of 1 m and mark the Snap to grid check box in order to ensure that objects align to the grid automatically when they are moved or positioned Praject Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Display iw Info bar jw Rulers v Origin Iw Points le Legend Same scale far and y axis Large cursor Iw Loads le Laver Colors Iw Forbidden lines Labels Layers Grid O As layer numbers i Show oid fv Snap to grid lw Loads As material numbers 7 Grid distance m 0 250 iw Forbidden lines As material names lw Layers Selection Accuracy 3 2 00 Save as default Cancel Help Figure 8 11 Project Properties window View Input tab 33 Select the Stresses Results tab Figure 8 12 to change the settings of the Stresses sec Deltares 127 of 264 D GEO STABILITY User Manual tion 8 8 3 and Stresses in Geometry section 8 8 2 windows 34 Select the As material names in the Layers sub window to display the material name of the different layers in the Stresses window Project Prop
47. Also the minimum safety factor found during the calculation thus far is displayed 75 Choose Start in the Calculation menu Start Search method Grid f Genetic algorithm Display le Graphic indicator le Short report Long report Cancel Help Figure 8 23 Start calculation window 76 Leave the Move grid Graphic indicator and Short report marked by default 77 Click OK At this point the calculation starts It is possible to view the progress of the calculation includ ing the minimum safety factor in a separate window Figure 8 24 as the Graphic indicator option was selected in the Start window Deltares 135 of 264 D GEO STABILITY User Manual Progress of Calculation Minimum safety factor so far 1 10 Figure 8 24 Progress of Calculation window See section 5 2 Start Calculation for a detailed description of this window 8 8 Results In the Results menu there are several possibilities to view the results of the calculation 8 8 1 Report To view a report text format that includes the input geometry and information about the critical slip circle 78 Choose Report from the Results menu 79 Go at the end of the short report to view information on the critical circle Figure 8 25 136 of 264 Deltares Tutorial 1 Dike reinforced with berm Se aie ete ai ak ale ak ak ak ak ak ake aie e See inte Sate ee aie e ak ak ak ake ai Sate aie Salat e e ate ee Seat II aky ak ade ake Sate
48. An alternative choice for uplift stability analysis Automatically finds a slip plane with minimum safety The plane consists of a horizontal part bounded by a circle active side and a straight plane passive side Compared to Van s method equilibrium is now also ensured for hori zontal forces Deltares 29 of 264 D GEO STABILITY User Manual Bishop prob random field Horizontal Bal ance Reinforcements A special module for advanced probabilistic design incorporating spatial variability This module formerly known as MProStab is described in chapter 21 To check the horizontal balance especially in case of seepage forces due to different water levels at the left and the right of a dike retaining water Mark the reinforcements used in the project Geotextiles Nails Soil Resistance Mark this check box to enable the usage of geotextiles in the project Mark this check box to enable the usage of nails in the project This button is available only if Nails is marked When clicking this button the Soil Resistance window appears Figure 4 2 in which the lateral and shear stresses criterion at the interface soil nails can be defined In Dowel action sub window the lateral stress along the nail can be defined in two ways H the lateral stress is defined as a stress curve distance from nail head vs ultimate stress for each nail if option Input of ultimate lateral stress alo
49. Angle bottom Average angle slice bottom Angle top deg Angle slice top at geometry surface m Length of slip circle for the slice approximated by a straight line Phi lde Internal friction angle at slice bottom Vertical water force on geometry surface at slice top Sw extr KN m Pore water pressure positive or negative at slice bottom Seow QUE due to degree of consolidation and PL lines at slice bottom Sw tot kN m Total water pressure at slice bottom S shear KN m Shear stress at slice bottom u KN m Shear strength s at slice bottom Horizontal stress ratio at slice bottom Ko JE kN m Effective vertical stress before loading at slice bottom Alf SigB kN m Alf is the degree of consolidation to the stress SigB result ing from the applied load Cu calculated Sig Alfa KN m Normal stress at slice bottom Bishop stress dependent In the case of a Spencer calculation the value position and angle of the inter slice forces are added to the output In the case of a probabilistic design a long report also shows the values of the influence factors and the values of all stochastic parameters at the design point Deltares 93 of 264 D GEO STABILITY User Manual If a column does not apply to a particular calculation method zeros are printed instead Report for Bishop Probabilistic Random Field model On the menu bar click Results and then select the Report option to open the Report wi
50. But if this mini mum length is only a quarter of the Reduction area then only a quarter of the tensile strength of the geotextile is taken into account NOTE This input must be determined by the user and depend on dif ferent factors such as the soil weight the ground structure According to a geotextile provider the Reduction area X can be determined using the following formula Oy 2tanpgx H xyx X where g is the effective tensile strength of the geotextile y is the fric tion angle with the soil H is the soil cover above the geotextile and is the unit weight of the soil In case of non horizontal surface the weight of the soil above above the geotextile has to be defined as a function of X 4 5 2 Nail Type Defaults In this window it is possible to define a default type of nail that can be used later in the Nails window section 4 5 3 For background information see section 16 2 2 3 Mail Type Defaults Length nail rn Diameter nail m 0 30 Diameter grout m 10 40 Yield force nail kM 200 00 Plastic moment nail kM m 1 50 00 Bending stiffness nail El kMnr 2 1 0E 08 Cancel Help Figure 4 67 Nail Type Defaults window Length nail Enter the length of the nail Diameter nail Enter the diameter of the nail Diameter grout Enter the diameter of the grout of the nail Yield force nail Enter the yield force in tension of the nail F obtained from a uni axial tensile test Plastic mome
51. Cancel Help Figure 4 75 Use MSeep Net window Mark this check box to confirm the use of the pressures in the se lected file Mark this check box to avoid contribution of pore pressures in unsat urated areas The Loads menu can be used to define loads in the geometry Line Loads The Line Loads option in the Loads menu displays an input window in which the line load per unit length in the direction perpendicular to the cross section are defined For background information see section 17 1 Magnitude X coordinate Y coordinate Direction Distribution Deltares Line Loads Load name Magnitude kM m 50 00 Line load 3 i ats A ef co ordinate m 146 10 Y co ordinate m 38 20 Direction deg 110 00 Line load 2 _ Add inser Distribution deg 25 00 Delete Rename y Cancel Help Figure 4 76 Line Loads window The load size per unit of length The horizontal coordinate The vertical coordinate The angle 0 between the load and the vertical axis The angle that defines the assumed load distribution relative to the direction of the load 0 lt lt 90 81 of 264 D GEO STABILITY User Manual Figure 4 77 Schematization of the angles 0 and for the definition of a line load 4 7 2 Uniform Loads The Uniform Loads option in the Loads menu displays an input window in which a uniformly distributed vertical surface load per unit of area are defined The part of the l
52. Deltares Tutorial 6 Reliability Analysis External Water Levels W Use water data later level Exceeding frequency Design level m 4 00 1A0000 1 2000 C 144000 1 1250 Decimate height m 10 30 Pllinez Water data name Mw Phreatic line number 3 Level Fl line Pine at tap at top 7 5 PE Es Ea PH ERANT Add Inizert al gt Delete Rename Copy from Geometry Cancel Help Figure 13 11 External Water Levels window MLW 13 7 Calculation and Results The input now includes stochastic values for soil properties and three different water levels have been defined These inputs are going to be included in a calculation that will result in a safety factor and a probability of failure for each water level 48 Click Start in the Calculation menu 49 Check that the Probabilistic calculation type is selected 50 Click OK While D GEO STABILITY performs the calculation the Calculation Progress window shows the current lowest safety factor for the water level that is being calculated 13 7 4 Stresses 51 Click Stresses in the Results menu to display the Critical Circle window Figure 13 12 The screen shows the failure mechanism for the design case The safety factor is the same as in Tutorial 1b section 8 9 3 with a value of 1 35 At the bottom of the screen the measurements of the slip circle are displayed Important to this tutorial are the safety factor and the probability of failu
53. GEO STABILITY D SETTLEMENT formerly known as MSettle MSeep and D GEO PIPELINE formerly known as MDrill For a full description of these programs and how to obtain them visit www deltaressystems com 4 3 6 Export as Plaxis DOS This option displays the Save As Plaxis DOS dialog that enables the user to choose a direc tory and a file name in which to save the current geometry The file will be saved using the old DOS style geometry format for the Deltares systems geo tools Files in this format can be used by the finite element program Plaxis and in old DOS based versions of Deltares Systems programs such as D GEO STABILITY DOS and MZet Saving files of this type will only succeed however if the stringent demands imposed by the old DOS style are satisfied number of layers 20 number of PL lines 20 number of lines per boundary lt 50 total number of points 500 To be able to differentiate between an old DOS style file and a normal geometry file the file dialog that prompts for a new file name for the old DOS style geometry file provides a default file name prefixing the current file name with a D 4 3 7 Limits Use this option to edit the geometry limits Geometry Limits Geometry Limits Boundary limit at left m 0 000 Boundary limit at right m 100 000 E Cancel Help Figure 4 45 Geometry Limits window A limit is a vertical boundary defining the end at either t
54. GEO STABILITY supplies defaults for the value of Fpartia that are based on the Dutch NEN code Probabilistic analysis The following subjects are specifically related to probabilistic analysis with D GEO STABILITY s Reliability module section 20 4 1 The probabilistic procedure FORM section 20 4 2 The assumptions and limitation when using this procedure section 20 4 3 The stochastic hydraulic pore pressure section 20 4 4 The stochastic excess pore pressure section 20 4 5 The stochastic external water level section 20 4 6 The stochastic model factor See section 21 5 for specific background on probabilistic analysis with the Bishop probabilistic random field model FORM procedure All combinations of parameter values where the safety factor equals the required value are together called the Limit State Surface The FORM procedure determines the most likely parameter combination on this surface the design point by iteratively calculating the probability of failure using a linearization of the limit state function Z Z fb required 20 19 D GEO STABILITY calculates the derivatives for the linearization numerically via small param eter variations perturbation method An example of the Limit State Surface is given in Fig ure 20 1 Deltares 243 of 264 20 4 2 D GEO STABILITY User Manual limit state function 0 u design point B U2 Figure 20 1 Limit Surface and Limit State
55. GEO STABILITY version 10 1 was released in 2011 The name of the program has changed D GEO STABILITY replaces MStab A genetic algorithm might be used to find the minimum center point in a calculation It is possible to find a Spencer slip plane with a genetic algorithm The correlation coefficients of soil groups probabilistic calculation is adjusted The error in Horizontal Balance calculation above phreatic line is solved It is possible to calculate with soil nails D GEO STABILITY version 14 1 2014 A Spencer plane has a zone number as well Zone Plot option The shear stresses per slice for Fellenius model are now correct The use of nails with the Uplift Van method is now possible D GEO STABILITY version 15 1 April 2015 This version implements some improvements For Horizontal Balance model a negative safety factor could be found This is now fixed A toggle button is implemented in the View nput Figure 2 5 to switch between same scale for X and Y axis and not same scale for X and Y axis Inthe Calculation Options window Figure 5 1 a range for the horizontal position of the Deltares 5 of 264 D GEO STABILITY User Manual entry point of the critical slip plane can be specified The Help file is no more available clicking on the Help button will open the User Manual in which a search by specific word can be performed The background section of the manual is improved for circular slip plane section 16
56. In practice the following guidelines are used to determine a value for the standard deviation when processing soil test results The input value of the standard deviation is composed of a statistical contribution of several factors 240 of 264 Deltares Reliability analysis inherent soil variability systematic uncertainty contribution by soil testing the transformation from measurements to parameters D GEO STABILITY assumes a homogeneous soil distribution For a complete description of the uncertainty in the soil the effect of spatial fluctuations in the standard deviation must be included A suitable expression for the standard deviation can be derived by applying Van Marcke s random field theory Van Marcke 1983 Combination of this expression with a systematic contribution yields 1 t 2 Ototal u Vaya EJ 1 Yu 1 ES r Irene 20 6 With 1 TU 2 2 O statistical mci p Ez E u 20 7 i 1 1 verticals I Nverticals 2 dd DS tistical 20 8 a Rer RT statistical D y max n E 1 20 9 layer where t is the parameter from a Student distribution which depends on the number of sam ples n The parameter becomes equal to u for large values of n Vsys is the coefficient of variation that quantifies the systematic uncertainty by soil testing and by the transformation from measurements to parameters A usual value is 0 1 for cohesion and 0 04 for the angle of friction Phoon and Kulha
57. Lateral Stress tab is available only if the option nput of ultimate lateral stress along nail was selected in the Soil Resistance window section 4 1 1 In this tab the lateral stress curve along the nail can be defined ultimate lateral stress vs distance from nail head 76 of 264 Deltares Input Nails Options for all nails Critical angle deg 5 Oo Geometry Nail Type Lateral Stress Shear Stress Mail name Lateral Stress Curve Mall 2 Mail 3 1 juna 0 00 sel 2 2000 130 00 sigma ultimate kim 0 0 5 0 10 0 150 200 Distance from nail head m Add Insert a Delete Rename 3 Cancel Help Figure 4 70 Nails window Lateral Stress tab 4 5 3 4 Nails Shear Stress The Shear Stress tab is available only if the option nput of ultimate shear stress along nail was selected in the Soil Resistance window section 4 1 1 In this tab the shear stress curve along the nail can be defined ultimate shear stress vs distance from nail head Nails Options for all nails Critical anale deg 5 a Geometry Nail Type Lateral Stress Shear Stress Mail name Shear Stress Curre Mall 2 Mail 3 m m E tu E a un 0 0 5 0 10 0 150 200 Distance from nail head m Add Insert a Delete Rename y 3 Cancel Help Figure 4 71 Nails window Shear Stress tab Deltares 77 of 264 D GEO STABILITY User Manual 4 06 Water menu The Water menu ca
58. Loads W Forbidden lines e Legend Same scale fors and y axis Large cursor iw Laver colors Layers Safety limits m Ags layer numbers Safe gt 1 35 Iw Loads Iw Forbidden lines Az material numbers fe As material names jw Layers 11 15 Fail lt Cancel Help Figure 4 10 Project Properties window Safety Results tab Info bar Mark this check box to display the information bar at the bottom of the Safety Results window Legend Mark this check box to display the legend with soil types Layer Colors Mark this check box to alter the default legend colors Rulers Mark this check box to display the rulers Same scale for Mark this check box to enforce the same length scale for horizontal and x and y axis vertical axis Origin Mark this check box to display the origin Large cursor Points Mark this check box to use the large cursor instead of the small one Mark this check box to display geometry points Loads Mark this check box to display loads Forbidden Mark this check box to display forbidden lines Lines Geotextiles Mark this check box to display geotextiles Labels Mark the check box of the elements Points Loads Forbidden Lines Geotextiles and Layers to display the labels of this element Layers ooil layers may be identified by their material name their index in the list of materials or their index in the list of layers in the soil profile Safe gt Enter the values that defi
59. Nails window Nail Type tab aooaa a a a 76 Nails window Lateral Stress tab 77 Nails window Shear Stress tab 2 a 77 Unit Weight of Water window 78 External Water Levels window 79 Degree of Consolidation window consolidation by soil weight 80 Use MSeep Net window 1 1 ee a a 81 Line Loads window 2 2 2 2 252 52 5 81 Schematization of the angles and for the definition of a line load 82 Uniform Loads window 1 a a a a a a 82 Earthquake window 2 6 a s 83 Tree on Slope window 1 a a a a a 84 Calculation Options window 2 a lll lll 85 Start window Grid method 87 Start window Genetic algorithm method 87 Options Genetic Algorithm window 88 Deltares 9 0 6 1 6 2 6 3 6 4 6 5 6 6 6 7 6 8 6 10 6 11 6 12 6 13 7 1 7 2 7 3 7 4 7 9 7 6 id 7 8 12 7 10 7 11 7 12 7 13 7 14 FAS 7 16 1 17 7 18 7 19 7 20 7 21 PRE 7 23 7 24 1 25 7 26 8 1 8 2 8 3 8 4 8 5 8 6 8 7 8 8 8 9 8 10 8 11 Deltares List of Figures Progress of Calculation window lll Report window for Bishop method ee eee Report window intermediate results Report window final results 2 lll rn Stresses in Geometry window
60. Safety window See section 4 4 4 Zone Areas for Safety for a detailed description of this window 15 4 Rest slope of the soil materials The slope of the rest profile depends on the soil type I for peat and sand and 5 for clay 16 Open the Materials window from the Soil menu 17 Leave the Rest slope of the Soft Clay to its default value lt 1 2 gt 18 Select the Peat material and define a Rest slope of lt 1 4 gt as shown in Figure 15 4 19 Do the same for the Sand material 20 Click OK Materials 33 Total unit weight iste ea name Above phreatic level EN rrr 12000 i Below phreatic level EN rr 120000 Shear strength model Default E phi Rest slope Z Cohesion c kM rr 5 00 Friction angle phi deg 115 00 Add Insert Delete Rename Cancel Help Figure 15 4 Materials window Deltares 199 of 264 D GEO STABILITY User Manual 15 5 Calculation and Results 15 5 1 15 5 2 To start the calculation 21 Choose Start in the Calculation menu to open the Calculation window 22 Click OK Safety Factor per Zone 23 Choose Safety Factor per Zone from the Results menu to open the Safety Factor per Zone window Figure 15 5 P Safety Factor per Zone oS Edit A 2 500 K e e e wi E E d o gone la o o Safety factor model factor Entry point active circle m Figure 15 5 Safety Factor per Zone window
61. Schematization Only available for Zone Plot model section 4 1 1 Extra model factor reduction factor used for the calculation of the stability of the deformed slip surface For background information refer to section 22 2 Its default value is set to 0 8 Deltares 85 of 264 D GEO STABILITY User Manual Use friction of end section Expected length of Sliding surface Minimum X entree used Minimum X entree Maximum X entree used Maximum X entree 5 2 Start Calculation Only available for Bishop model section 4 1 1 Select this button to include the stability increase caused by the resistance at the edges of a sliding section in the out of plane direction For background in formation refer to section 16 2 2 4 Only available for Bishop model section 4 1 1 If the option Use friction of end section is enabled enter the length of the considered section in the out of plane direction Select this button to used a minimum X coordinate for the entry point of the slip plane Slip planes with an entry point situated at the left of this point will not be retained during the search procedure of the critical slip plane If the option Minimum X entree used is enabled enter a minimum X coordinate for the entry point of the slip plane Select this button to used a maximum X coordinate for the entry point of the slip plane Slip planes with an entry point situated at the right of this point will not be retained during the sear
62. Total unit weight r aiznel neme Above phreatic level KM rr 3 00 Clay clean moderate Clay clean stiff Below phreatic level kN 4rr 121 Un Clay clean weak Clay organ moderate Clay organ weak Clay sl san moderate Stress table Curve 1 r Clay sl san stiff Clay sl san weak Soil group Soil Group Sand hal Clay ve zan stiff Sand clean loose Sand clean moderate Sand clean stiff Sand sl sil moderate Sand ve sil loose Add Insert a Delete Rename Soil Groupe Figure 4 29 Materials window for Pseudo values shear strength model with Global mea surements Click the Soil Groups button at the bottom of the Materials window to open the soil Groups 3 Soil Groups window see Figure 4 30 Deltares 47 of 264 D GEO STABILITY User Manual Soil Groups Group name Selected in group Soil Group Clay Soil Group Sand Clay sl zan moderate Clay sl zan stiff Clay sl zan weak Clay ve san stiff Add Insert Delete Rename y Cancel Help Figure 4 30 Soil Groups window In this window it is possible to define soil groups Click on the Add button to create a new Soil Group Select a material in the eue available list of soil materials called Ungrouped at the right side of the window Click on the Select highlighted material button to add the selected material to lt the selected soil group Click on the Select all materials button to a
63. X co ordinate of line load in m Ui is the Z co ordinate of line load in m is the load distribution angle in degree Refer to section 4 7 1 Line Loads for the input Deltares 223 of 264 D GEO STABILITY User Manual do Figure 17 1 Line Load Note The line load can be situated in or above the soil structure Besides an increase of the total stress line loads located in the confines of the slip circle also contributes to the driving moment of the slip circle This moment is added to the driving load moment 17 2 Uniform loads A permanent or temporary vertical uniform load can be applied on a surface area In the direc tion perpendicular to the geometry plane the load is assumed to be infinite The magnitude the start and end X coordinate and a distribution angle for the load must be specified For temporary loads a table of the degree of consolidation must be specified 224 of 264 Deltares Loads AOg Figure 17 2 Uniform Load The increase is calculated using the following formula ax Q x T2 21 A pe LR ARAS E WM 2 21 2 y1 yo X tan 17 2 Ac _ is the increase of the total stress in kN m Q is the magnitude of the distributed load in KN m X1 is the horizontal co ordinate where load starts in m Ui is the vertical co ordinate where load starts in m X is the horizontal co ordinate where load ends in m Ub is the vertical co ordinate at the bottom
64. and its saturated weight A material can be connected to a layer in order to define the soil type of the layer Limits A limit is a vertical boundary defining the end at either the left or right side of the geometry It is defined by an X coordinate only Note that this is the only type of element that cannot be deleted Adding moving and deleting the above mentioned elements are subject to the conditions for a valid geometry see section 7 2 For example while dragging selected geometry elements the program can perform constant checks on the geometry validity section 7 4 4 Invalid parts will be shown as construction elements thick blue lines Deltares 103 of 264 7 2 7 3 D GEO STABILITY User Manual Construction elements Besides the D GEO STABILITY geometry elements section 7 1 1 special construction elements can also be used for sketching the geometry graphically These elements are not a direct part of the geometry and the restrictions on editing adding moving and deleting these elements are therefore far less rigid The only restriction that remains is that these elements cannot be moved and or defined beyond the limits of the geometry Lines A line consists of a starting point and end point both defined by a left hand mouse click in the graphic input screen Poly lines A poly line consists of a series of connected lines all defined by a left hand mouse click in the graphic input screen Construction e
65. at o 41 for a layer part above the groundwater level 18 2 Cag Ysat Yw X h for a layer part below the groundwater level where h is the thickness of the layer part in m Yunsat is the unsaturated i e dry unit weight of the soil in kN m a s the saturated i e wet unit weight of the soil in kN m Vw is the volumetric weight of the water in kN m The pore pressure induced by the degree of consolidation U in layer 2 by addition of layer 7 k i 100 U 1 u JS Op vA m 18 3 poc 2 gt 2 o 100 18 3 i l j 1 where k is the number of layers Tyi is the effective vertical stress in layer 2 see Equation 18 2 p is the relative degree of consolidation in layer 2 due to layer 7 in as defined in the Degree of Consolidation window section 4 6 3 230 of 264 Deltares 18 4 18 5 Pore pressures Examples of excess pore pressures by soil self weight Table 18 1 shows an example of a three layered soil structure where there are different de grees of consolidation Table 18 1 Different degrees of consolidation in different layers Layer 2 Degree of by addition Effective Pore top to bottom consolidation of layer 7 stress pressures in layer 2 The effective stress at the bottom of a slice in layer 3 is equal to 60 of the effective weight of layer 1 plus 90 of the effective weight of layer 2 plus 100 of the effective weight of the part of layer 3 above the bottom
66. calculate the unfavorable characteristic value of co dev hesion and friction angle section 20 3 4 section 20 3 5 Stochastic Calculated undrained cohesion Cu Shear strength model Cu calculated Standard Shear strength input Default Mean ke Use probabilistic defaults Advanced Ratio undrained strength Cu preconsolisdation stress Pc Mean Horizontal D55 10 22 10 12 10 06 Log normal Mean FOF kM Am 110 00 17 67 11 00 Log normal Figure 4 36 Cu calculated Standard stochastic input Ratio Cu Pc The ratio between the undrained cohesion s and the vertical pre consolidation stress pe section 19 3 Values range typically between 0 18 and 0 26 Average values for horizontal orientation of the slip plane are derived from example from Direct Simple Shear DSS tests Deltares 51 of 264 D GEO STABILITY User Manual POP The pre overburden pressure D GEO STABILITY uses this value to calcu late the pre consolidation stress p from the effective vertical stress Pe max c POP oj U TE The reference value of the vertical stress is determined from a refer ence level of the historic ground surface see the Definitions menu sec tion 4 4 4 Shear strength model Cu calculated Standard Shear strength input Default Mean jw Use probabilistic defaults le Advanced Shear Strength Shear Strength Advanced Fore Pressure Ratio undrained strength Cu preconzolidation str
67. consolidation ensures that part of the vertical acceleration results in an increase in effective stress The other part results in excess pore pressure The excess pore pressure tquake excess generated by the earthquake is ki Uquake excess Gy Y x h X 1 Bj 17 5 j l where Q4 is the vertical earthquake factor i e acceleration coefficient as defined in the Earthquake window in section 4 7 3 hj is the thickness of layer 7 in slice 2 lc is the number of layers along slice 2 D is the degree of consolidation of layer 7 0 lt 6 lt 1 as defined in the Earth quake window in section 4 7 3 Yj is the unit weight of soil layer 7 in slice in kN m Refer to section 1 8 for the definition of the other symbols Additional pore pressure at the bottom of the slice The additional pore pressure includes the change in hydrostatic pressure as well as the ex cess pore pressure due to vertical quake component Uquake hydro X Gy Uquake excess 17 6 where Unido is the hydrostatic pore pressure in KN m Uhydro Max IA sc uS Z X Yw 0 Q4 is the vertical acceleration coefficient Uquake excess S the excess pore pressure due to the earthquake in kN m see Equa tion 17 5 Water moment The free water coefficient simulates the temporary draw down of the water The free water moment is modified according to equation Mowater quake Mob water X Cfw 17 7 where Mo water is the driving water moment in kNm
68. curve with a last horizontal branch In the Sigma Tau Curves window see Figure 4 12 itis possible to specify different sigma tau curves Figure 4 12 gives an example a user defined sigma tau curve Sigma Tau Curves L urve name Sigma Tau Curve Curve 1 E E z s E 0 0 100 200 300 400 500 Sigma KN m Add Insert Delete Rename y Import Cancel Help Figure 4 12 Sigma Tau Curves window for deterministic design Import predefined Curves Alternatively it is possible to use predefined Sigma Tau curves To do so place a file with oigma Tau data called Tausigma dat in the D GEO STABILITY Install directory Import When clicking the Import button the Import Stress Table window appears Figure 4 13 This window contains predefined Sigma Tau curves for different kind of soil Deltares 39 of 264 D GEO STABILITY User Manual Import Stress Table Calais B Calais M Calais O Duinkerke B Duinkerke M Duinkerke O Hollandween B Hollandyveen M Hallandveen O 0 AL Basisveen Gorkum Licht Gorkum Zwaar Hollandyeen Kreftenheye Tiel J Basisveen Cancel Help Figure 4 13 Import Stress Table window After selecting the desired curve and clicking OK this curve is added to the others manually inputted curves in the Sigma Tau Curves window Figure 4 14 Sigma Tau Curves xm Curve name Sigma Tau Curve Btw AL
69. drawing Same scale for X and Y axis Click this button to use the same scale for the horizontal and vertical directions Undo Click this button to undo the last change s made to the geometry Redo Click this button to redo the previous Undo action Automatic regeneration of geometry on off When selected the program will automatically try to generate a new valid geom etry whenever geometry modifications require this During generation poly lines solid blue are converted to boundaries solid black with interjacent layers New layers receive a default material type Existing layers keep the materials that were assigned to them Invalid geometry parts are converted to construction elements Automatic regeneration may slow down progress during input of complex geome try because validity will be checked continuously Delete Click this button to delete a selected element Note that this button is only available when an element is selected Add forbidden lines Click this button to display a window in which it is possible to add modify or delete lines Slip circles are not allowed to cross forbidden lines Add line loads Click this button to display a window in which it is possible to add modify or delete point loads per unit of length Add uniform loads Click this button to display a window in which it is possible to add modify or delete uniform loads per unit of area Edit tree on slope Click this button to display a window
70. e Xm 52 14 m Radius 22 07 m Max isoline 2 19 Mo of isolines 11 Ym 18 43 m Safety 1 48 Min isoline 1 48 X 55 802 Y 18 856 Edit Figure 13 14 FMin Grid window 13 7 3 Influence Factors To get an idea of what parameters in the input contribute most the final outcome of the calcu lation 54 Click nfluence Factors in the Results menu In the nfluence Factors window displayed the results for the different external water levels can be seen using the drop down menu at the top In addition this menu also includes the Design point water level which is equal to 3 06 m in this tutorial 55 Select Design point water level 3 06 m from the drop down menu The window displayed Figure 13 15 shows that the Model Factor has a large influence on the outcome of the safety factor and the slope s probability of failure Deltares 191 of 264 D GEO STABILITY User Manual rex m2 Influence 96 m Figure 13 15 Influence Factors window 13 8 Conclusion The Reliability Analysis in D GEO STABILITY is able to perform a probabilistic calculation in corporating stochastic description of soil properties as well as probabilistic descriptions of external water levels A design conclusion is that for cases with higher water levels the safety factor is lower 192 of 264 Deltares 14 Tutorial 7 Bishop Random Field Method 14 1 The case from Tutorial 6 chapter 13 is used in t
71. e ade ete ai et Seat aie ade ale aky ak Set ade ade ade Seat e See ee ate et Seat ate ade ade ne ede de de be Sale dde 13 43 1 r T AAA AAA ALEA The input has been tested end is correct EEE EEE de d dod d d odecd d dp de ode de cde d de de de de cde de de ode od dp d d de ode de ode ode d decode ode od d d d dpod d d d d de d d d do de de RESULTS OF THE SLOPE STABILITY ANALYSIS Information an the critical circle Fmin 1 104 Calculation method used Bishop C phi X co ordinate center point E 46 43 m Y co ordinate center point E 7 71 m Badius of critical circle E 11 36 m The center point of the critical circle is enclosed Driving moment soil B 3159 01 kNm m Driving moment free water E 0 00 kNm m Driving moment external loads 0 00 kNm m Iterated resisting moment E 3153 01 kNm m Non iterated resisting moment E 3460 60 kNm m END OF D Geo Stability OUTPUT Figure 8 25 Report window Note It is possible to export the report shown in the Report window to a text file When the Report window is active choose Export Active Window in the File menu In fact it is possible to export any active window within D GEO STABILITY Windows that contain geometrical infor mation can usually be exported to a Windows Meta File wmf or a Drawing exchange file for AutoCAD 14 dxf See section 6 1 Report for a detailed description of this window 8 8 2 Stresses in Geometry To view the st
72. geotextile or forbidden line Items can then be deleted or modified by dragging or resizing or by clicking the right hand mouse button and choosing an option from the menu displayed Pressing the Escape key will return the user to this Select and Edit mode Pan cul Click this button to change the visible part of the drawing by clicking and dragging the mouse Add point s to boundary PL line Click this button to add points to all types of lines lines polylines boundary lines PL lines By adding a point to a line the existing line is split into two new lines This provides more freedom when modifying the geometry E 16 of 264 Deltares q h Deltares Getting Started Add single lines s Click this button to add single lines When this button is selected the first left hand mouse click will add the info bar of the new line and a rubber band is displayed when the mouse is moved The second left hand mouse click defines the end point and thus the final position of the line It is now possible to either go on clicking start and end points to define lines or stop adding lines by selecting one of the other tool buttons or by clicking the right hand mouse button or by pressing the Escape key Add polyline s Click this button to add poly lines When this button is selected the first left hand mouse click adds the starting point of the new line and a rubber band is displayed when the mouse is moved A
73. go through the steps needed to set up the basic geometry of the project Later in this tutorial the user shall also make slight alterations to the geometry manually 120 of 264 Deltares 8 2 1 8 2 2 Tutorial 1 Dike reinforced with berm Wizard Basic Layout The first Wizard window sets the basic geometrical properties of the project Figure 8 3 8 New Wizard Define measurements basic layout Ground Level Phreatic Level Limit Lett Limit Right Limit left m 0 00 Limit right m 500 8 Number of layers mas 10 iS Ground level m CS Phreatic level m ECTS Cancel Help Figure 8 3 New Wizard window Basic geometrical properties Determine the boundaries of the calculation domain by checking if the left and right limits are lt 0 m and 75 m gt respectively Set the number of layers to 3 Leave the ground level at O m In this tutorial there is a higher water level left of the dike Set the phreatic level to lt 4 m gt This will set the phreatic level to 4 m across the whole domain Later it will be modified manually according to Figure 8 1 Click Next Note Usually the left limit is O m and the right limit is in the order of two times the width of the soil structure to be modeled Wizard Shape selection In the next window Figure 8 4 several basic geometric situations can be selected In this tutorial a dike structure without berm but with a dewat
74. gt Select Soft Clay in the material list and rename it into lt Clay gt Delete the unused materials by selecting them and clicking the Delete button Enter the soil properties values of the four layers used in this tutorial Clay Peat Sand and Dike Sand as indicated in Table 12 1 Click OK when finished Geometry With the Geometry menu it is possible to modify the current geometry as given in Figure 12 1 Points The geometric values of the different layers need to be adjusted and two points need to be added to create a second PL line called PL line 2 in Figure 12 1 at level 1 5 m 18 19 20 21 Click Points in the Geometry menu to open the Points window Click two times the Add row button to add points number lt 17 gt and lt 18 gt which will be used to create PL line 2 see section 12 5 2 Modify the coordinates of points number lt 1 gt till lt 18 gt as given in Figure 12 5 Click OK 176 of 264 Deltares Tutorial 5 The Uplift Van model 12 5 2 PL lines To create PL line 2 follow these steps 23 Click PL lines in the Geometry menu to open the PL Lines window 24 Click the Add button to add PL line number lt 2 gt 25 Enter points number lt 17 gt and 18 in the Point number column at the right of the PI Lines window Figure 12 6 26 Click OK 0 000 1 500 100 000 1 500 d Insert Delete Cancel Help Figure 12 6 Pl Lines window 12 5 3 PL lines per Laye
75. in the Soil Resistance window Figure 4 2 then Tmax IS determined using the table inputted in the Shear Stress tab of the Nails window Figure 4 71 using distance Lsnear If Input of bond stress diagram sigma tau is selected in the Soi Resistance window Figure 4 2 then Tmax is determined using the table inputted in the Bond Stress Diagrams window Figure 4 17 is the borehole diameter in m is the adherence length beyond the failure surface in m is the distance from nail head used in the shear stress curve L Tmax curve in L 0 5 L if no facing or bearing plate is used and if Ly lt Lo 0 5 L if no facing or bearing plate is used and if L gt L is the length from failure surface to end nail in m is the length from failure surface to head nail in m Ly L Ly m L 0 5 L if facing or bearing plate is used Lshear ET 211 of 264 D GEO STABILITY User Manual 16 2 2 3 2 Soil nail normal reaction soil fails in bearing below the nail The nail is consider as a beam on elastic supports i e soil d Ec gts 16 17 dz where EI _ isthe stiffness of the nail in kNm E is the Young s modulus of the soil determined from the following empirical formula in kN m AXO in XA CR x 2 65 Za Q is the rheological coefficient of the soil in m CR isthe compression ratio of the soil C COR 1 0 O is the effective stress of the soil at the intersection point betwee
76. in which it is possible to input an area on the slope where trees are present See section 7 3 2 in the Graphical Geometry Input chapter for more information on how using those buttons Info bar This bar situated at the bottom of the View Input window displays the coordinates of the current position of the cursor and the distance between two points when the icon Measure the distance between two points is selected from the Edit panel 18 of 264 Deltares 2 2 5 2 2 6 2 3 2 4 2 4 1 Getting Started Table 2 1 Keyboard shortcuts for D Geo Stability Save As Sass ooo Title panel This panel situated at the bottom of the main window displays the project titles as entered on the Identification tab in the Project Properties window section 4 1 3 Status bar This bar situated at the bottom of the main window displays a description of the selected icon of the icon bar section 2 2 2 or of the View Input window section 2 2 3 Files Input file ASCII Contains the D GEO STABILITY specific input with the problem description After interactive generation this file can be reused in subsequent D GEO STABILITY analysis Input file ASCII Contains geometry data resulting for example for a settlement analysis with D SETTLEMENT formerly known as MSettle Output file ASCII After a calculation has been performed all output is written to this file If there are any errors in the input they are described in t
77. line Number at top at bottom hi B 5 5 Figure 11 9 PL lines per Layer window 162 of 264 Deltares Tutorial 4 The Spencer Method Table 11 2 Degree of consolidation per layer Effect of layer 6 Effect of layer 5 a e 11 2 6 Degree of Consolidation The weight of the top layers of the dike will cause excess pore pressure in some layers Part of the excess pore pressure is still present in the less permeable layers The dissipation of pore pressure is expressed in the degree of consolidation E g when 60 of the excess pore pressure has dissipated the degree of consolidation is 60 Let assume that layer 4 stiff clay is affected by layer 6 50 of the excess pore pressures in layer 4 have dissipated Similarly some of the lower layers are affected by layer 5 In Table 11 2 the degree of consolidation due to the influencing layers is given To input this perform the following steps 22 From the Water menu choose the Degree of Consolidation option 23 In the window displayed select for Effect of layer number 6 change the degree of consol idation in layer 4 to 50 in layer 3 to 40 and in layer 2 to 30 according to Table 11 2 The Degree of Consolidation window should be as Figure 11 10 Degree of Consolidation J Use under everpressures above phreatic line Effect of layer E on consolidation of laver s Degree ofconzolidation Cancel Help Figure 11 10 Degree of Cons
78. m Safety 1 10 Min stress 4 634 kN m2 X 53 548 Y 12 184 E dit Figure 8 29 Shear stresses window along the slip circle oee section 6 3 Stresses for a detailed description of this window 8 8 4 FMin Grid To see an overview of the safety factors within the grid 84 Choose FMin Grid in the Results menu In the FMin Grid window displayed Figure 8 30 the isolines connect point with equal values for the safety factor The variations of the safety factors within the grid are within an accept able margin of each other When the differences are larger it is advisable to perform a new calculation with a finer grid 9 Fivin Grid Edit 4 B dw x 10 52 a i c ME Tools amp 1 129 E 1 115 1 151 1 156 E to 1 125 m 1 153 re a E E 124 an E Yh 14 E 124 um s F 126 da E i 129 Dh E t eo l sz 50 Xm 46 43 m Radius 11 36 m Max isoline 1 41 No of isolines 11 Ym 7 71 m Safety 1 10 Min isoline 1 10 X 49 440 Y 10 899 Edit Figure 8 30 FMin Grid window 140 of 264 Deltares 8 8 5 Tutorial 1 Dike reinforced with berm Note Values of 1 indicate the impossibility of calculation See section 6 4 FMin Grid for a detailed description of this window Safety overview To view the areas with particular ranges of safety factor 85 Click Safety Overview option in the Results menu In the Safety Overview window displayed Figure 8 31 the gree
79. model For this example the following D GEO STABILITY module is needed D GEO STABILITY Standard module Bishop and Fellenius This tutorial is presented in the file Tutorial 8 sti 15 1 Introduction to the case The Zone Plot model divides the body into six parts as shown in Figure 15 1 17 5m 6 0m 10m 8m 3m 2 5 1 5 1 5 3 3 5 Figure 15 1 Geometry overview Tutorial 8 The required safety factors for the different zone areas are given in Table 15 1 The geometry soil properties and external water levels shown in Figure 15 1 are the same as Tutorial 1a 1 Click Open in the File menu Table 15 1 Required safety factors for the zone areas of the Zone Plot model Required safety factor 119 Al 1 02 CIN mo o so o Deltares 197 of 264 15 2 15 2 1 15 2 2 15 3 D GEO STABILITY User Manual Select Tutorial 1a Click Open Click Save as in the File menu Enter lt Tutorial 8 gt as file name Click Save e e e Im Project Model 7 Click Model in the Project menu 8 Mark the Zone plot check box 9 Click OK Model Model Default shear strength f Bishop i phi f Spencer f Stress tables f Fellenius Cy calculated f Uplift Yan Cy measured f Uplitt Spencer f Cy gradient f Bishop probabilistic random field f Pseudo values Honzontal balance Reinforcements Reliability analysis Geotextiles Enable Nails zone plot Cancel Help
80. moment from end section The resisting moment is increased by Mr end section the resistance at the edges of a sliding section in the out of plane direction due to the undrained shear strength 1 MR end section F 7 Y IC X x M 16 27 with hj Mj su hj Suj min Ze Zj avg 2 Su j bot Sujjitop Ze Zj cg Su j min min Care bot in q Zira Zion J avg Mio et ee J u j top u j bot ane ad l 2h5 3 If Susjtop gt Su j bot where F is the safety factor see Equation 16 28 in section 16 2 3 hj is the thickness of layer 7 in slice 7 ki is the number of layers along slice 2 L is the expected length of the sliding surface in the out of plane direction i e cross section perpendicular to the cross section plane as defined in the Calculation Options window in section 5 1 n is the number of slices Su jbot IS the undrained shear strength at the bottom of layer 7 in slice 2 Su jtop S the undrained shear strength at the top of layer 7 in slice 2 Z j bot is the level at the bottom of layer 7 in slice 2 Zjiip isthe level at the top of layer 7 in slice 2 Refer to section 1 8 for the definition of the other symbols Note This extra resisting moment is calculated only if the option Use friction of end section 16 2 3 in the Calculation Options window section 5 1 is enabled and only for the Bishop model in combination with an undrained shear strength model Safety factor The safety factor P for
81. number for this water level is defined by line number 27 In other words all the weight of the soil beneath this level will be calculated by its weight under the phreatic line To include this in the calculation select phreatic line number 2 from the drop down menu Deltares 187 of 264 D GEO STABILITY User Manual 40 Enter lt 3 5 m gt for Level In combination with the design level and its frequency of ex 41 42 43 44 45 46 4T ceeding an exceeding frequency is established for this particular water level At this particular water level some of the layers piezometric levels differ Enter PL line at top and PL line at bottom according to the values shown in Figure 13 10 External Water Levels W Use water data Water level Exceeding frequency Design level m 4 00 C 1410000 c 1 2000 f 1 4000 f 1 1250 D ecimate height m 0 30 PHines Water data name Phreatic line number Pl line Pl line at top at top 4 Copy from Geometry Cancel Help Figure 13 10 External Water Levels window MHW To add the second water level to the calculation input click Add in the Water data name sub window Change the name of this water level to lt MLW gt Mean Low Water In the PL lines sub window the Phreatic line number for this water level is defined by line number 32 Set Level to 3 0 m For all the layers enter lt 3 gt as PL line at top and PL line at bottom Click OK 188 of 264
82. of a slice in m Ut is the vertical co ordinate at the top of a slice in m is the distribution angle of the load in degree Q is the degree of consolidation for the load 1 in case of permanent loads Refer to section 4 7 2 Uniform Loads for the input Besides an increase of the total stress the load also contributes to the driving moment of the slip circle The part of the load located within the confines of a slip circle creates a moment around the slip circle center point This moment is added to the driving load moment see Equation 16 7 in section 16 2 1 3 Deltares 225 of 264 17 3 17 3 1 17 3 2 D GEO STABILITY User Manual Earthquake In D GEO STABILITY it is possible to simulate the influences of earthquake forces The earth quake forces induce several forces stresses and moments The influences of these earth quake forces are incorporated in D GEO STABILITY by so called earthquake coefficients These coefficients give the mass of soil and water an additional horizontal and vertical ac celeration To simplify the calculation it is assumed that the groundwater in the soil mass has the same extra acceleration as the soil in this mass Note For the free water on the slope a different coefficient must be specified Additional moment due to horizontal acceleration The driving moment of slip circles increases due to the earthquake coefficients This extra moment Mp soil quake H Called additional ho
83. of consolidation of 10096 means no additional excess pore pressures See section 18 3 for background information 4 6 4 Use MSeep net Choose the Use MSeep Net option from the Water menu to import hydraulic pore pres sures from a previous MSeep analysis MSeep software stationary groundwater flow cal culations calculates water pressures and phreatic lines When using this option MSeep and D GEO STABILITY should share the same geometry so that D GEO STABILITY can use the MSeep dump file SED to obtain the water pressures The MSeep dump file contains a list of nodes with their X and Y coordinates and the calculated water pressure at each node The file also contains information on the position of the phreatic line which in D GEO STABILITY forms the boundary between dry and wet soil All nodes in the MSeep dump file are drawn as dots and should cover the D GEO STABILITY geometry at all places below the phreatic line In some cases MSeep calculates negative water pressures when a phreatic block be comes too thin see MSeep for more information If negative water pressures are present the D GEO STABILITY user can select whether these should be equal to zero 80 of 264 Deltares 4 7 4 7 1 Use the water net of the selected MSeep file Make negative pressures zero Loads menu Input Use MSeep Met MSeep file Browse exemple sed w Use the water net of the selected MSeep file je Make negative pressures zero
84. of the dike Left side of the road construction at the polder side of the dike Right side of the road construction at the polder side of the dike Required safety factor in zone 3a of the dike Hequired safety factor in zone 3b of the dike select Left side or Right side to design the polder side of the dike Zone area s for safety are developed for conditions with little over topping If the flow due to overtopping is more than 0 1 l m s all circles are classified as Zone 1 Polder Figure 4 64 Schematization of the zone areas for the Zone Plot model 72 of 264 Deltares 4 4 5 4 5 4 5 1 Input Reference level for Ratio Cu Pc In this window it is possible to define a reference surface level This option applies only to the calculated undrained strength model section 4 2 3 1 section 4 2 3 2 It is appropriate to use the reference level if an embankment has been added to initially over consolidated soil Reference Level for Ratio Cu Pc Initial surface level Cu calculated only Top of layer Dike sand Cancel Help Figure 4 65 Reference Level for Ratio Cu Pc window Top of layer Select the top of the layer that will be used as the reference level sec tion 19 3 Reinforcements Geotextiles In this window see Figure 4 66 it is possible to add geotextiles to the cross section For background information see section 16 2 2 2 Geotextiles 3eatextile number Effective tensile strength
85. of the slice The excess pore pressure at the same spot is equal to 100 60 40 of the effective weight of layer 1 plus 100 90 10 of the effective weight of layer 2 plus 100 100 0 of the effective weight of the part of layer 3 above the bottom of the slice This example assumes that the phreatic line is located above layer boundary 2 By defining the degree of consolidation for the load of each layer above the actual layer and for the weight of the actual layer itself it is possible to simulate different stages of a construction process If for example one extra layer is placed on the surface as a new load the early stages of construction can be calculated by assigning a low degree of consolidation in underlying layers with low permeability due to the weight of the new layer For points above the phreatic line it is possible to choose whether pore excess under pres sures are to be used to affect the effective stress Pore pressure from temporary distributed loads The extra pore pressure due to temporary distributed loads is Vioad 100 where Uload is the degree of consolation due to the temporary load as defined in the Uniform Loads window in section 4 7 2 Ag z is the increase of the total stress at depth z due to the temporary uniform load see Equation 17 2 in section 17 2 Total pore pressure and effective stress The total pore pressure u is obtained by adding the following contributions u
86. pressures and first order second moment probabilistic reliability analysis The probability of the external water level can be taken into account optionally 1 4 4 Product integration D GEO STABILITY is an integrated component of the Deltares Systems tools This means that it is possible to exchange relevant data with MGeobase central project environment D SETTLEMENT formerly known as MSettle transient settlements MSeep seepage and D GEO PIPELINE formerly known as MDrill pipeline installation Besides the exchange of input data D GEO STABILITY can also import a settled geometry calculated by D SETTLEMENT or a pore pressure load generated by MSeep MGeobase is used to maintain a central project database with measurements soil properties and geometry MGeobase offers power tools to create geotechnical profiles and longitudinal cross sections automatically from measure ments MGeobase can also use D GEO STABILITY to perform a batch stability analysis for multiple cross sections 4 of 264 Deltares General Information 1 5 History D GEO STABILITY was first named MStab and developed at GeoDelft Deltares in 1987 1988 with the support of both Oranjewoud BV and the Road and Hydraulic Engineering Division of the Ministry of Transport and Public Works MStab version 1 0 was first released in 1988 and has since been upgraded a number of times each time adding new features and improving its user interface to suit the new demands of its us
87. procedure until it finds a minimum safety factor that does not lie on one of the outer grid points Note A coarse grid produces less accurate information on the position of the slip circle with the lowest safety factor A possibility is to define a coarse grid to find the position of the slip circle with the minimum safety factor Then repeat the calculation with a finer grid that cover the coordinates associated with the minimum safety factor in the foregone calculation 134 of 264 Deltares 8 7 Tutorial 1 Dike reinforced with berm See section 4 4 1 1 Slip Circle Definition Bishop or Fellenius for a detailed description of this window Calculation At this point all the necessary project input has been given to start a calculation Before start ing the calculation there are some options which can be selected concerning the calculation and the kind of user preferred results report for the program to generate This can be done in the Start window Figure 8 23 The Move grid option allows the program to move the grid when it finds a minimum safety factor at one of the outer grid points The grid will then shift one grid spacing As these grid Spacings are user defined this can possibly result in a slightly differing safety factor Not selecting this option means that the calculation will only produce a minimum safety factor within the given grid The Graphic indicator shows the different slip circles as the program calculates
88. rest moment is less than e The complete iteration process is ended when the absolute values of both the rest force and the rest moment are less than 10 As a starting value a 220 of 264 Deltares CiL Pad sin a Di E G sin o W L sin a 5 S ess 16 5 Method of slices safety factor of 1 1 is assumed The program calculates a starting value for in the following Way Dum On x Ostart EN 16 39 In the calculation of the interslice forces from Equation 16 36 a division is made by factor cos a 6 MEM 16 40 At a certain combination of 6 and F this can lead to a division by zero This critical combina tion can be found by tan q sin a 6 cos a 6 0 16 41 F This leads to h i min O4 E arctan 16 42 tan p or Fs i max Q arctan 16 43 i tan p With this the critical values of 0j max and 0 min can be calculated as a function of the starting value of F The maximum of all T A iS max The denominator of formula 2 includes cos 0d The denominator becomes zero when 6 5 7 or 5 m When min is less than i Tr then Omin i m T When max is larger than 5 T then max 5 Horizontal Balance This paragraph describes the background of the Horizontal Balance calculation method Dif ferent water levels at the left and the right of a dike body causes seepage forces that change the earth pressures The h
89. spatial variability as a result of large and small scale differences in space and in time of the deposition regime and loading conditions during its geological history The purpose of soil investigation is to model the relevant patterns of spatial variability as accurately as possible Common soil investigation acquires data at single spatial points of the deposit or semi continuous data at distinct lines In general soil investigation programs allow fairly accurate modeling of the global patterns of variability such as soil stratification and average trends of variation of soil properties Patterns of small scale variability within each soil layer however remain unrevealed and evaluation of its effects on stability of slopes can only be dealt with by Statistical analysis In the Bishop probabilistic random field model the following assumptions regarding the geo metrical soil model and soil properties have been adopted The geometry of soil layers is considered to be deterministic data no uncertainty about geometrical data is taken into account From earlier reported studies on probabilistic stability analysis Alonso 1976 it may be concluded that spatial variability of unit weights is of minor importance Therefore this parameter is also left out of consideration in the stochastic model both for the soil and the water The background on the stochastic model for the pore pressures is equal to D GEO STABILITY s reliability m
90. tangent line are supplied It is possible to use a rather coarse grid with a sufficiently large horizontal range D GEO STABILITY will refine the grid automatically around the area with the lowest safety factor For more information on Van s theory see section 16 3 For more information on Spencer s theory see section 16 4 For an example of usage see Tutorial 5 section 12 6 Slip Plane Definition Grid left left m 25 000 Y top fight m 30 ooo bottom Number le Number Grid right left m 55 000 Y top A nght m 60 000 Y battom Number le Humber Tangent line top m 3 000 Automatic at boundaries bottom m 5 000 Number 3 Cancel Help Figure 4 57 Slip Plane Definition window Uplift Van and Uplift Spencer methods Deltares 67 of 264 D GEO STABILITY User Manual Grid left right X left The initial horizontal coordinate of the leftmost center point in the moving trial grid X right The initial horizontal coordinate of the rightmost center point in the moving trial grid Number The number of grid points in horizontal direction Y top The initial vertical coordinate of the highest center point in the moving trial grid Y bottom The initial vertical coordinate of the lowest center point in the moving trial grid Number The number of grid points in vertical direction Tangent Line Y top The initial vertical coordinate of the highest tangent line of a trial slip circle
91. the coordinates can be checked and modified if needed 94 Click OK 95 Repeat this verification for points 12 and 13 using Table 8 2 X co ordinate m 46 500 Y co ordinate m 2 000 Z co ordinate m 0 000 cores Figure 8 35 Point 11 properties window Deltares 143 of 264 D GEO STABILITY User Manual 8 9 2 Soil material assigned to the berm The soil material lt Berm Sand gt previously defined section 8 5 is assigned to this berm 96 In the Geometry tab of the View input window click the name Undetermined in the berm geometry When selected the name becomes red 97 Then right click and choose Properties TheLayer 5 propertieswindow will appear 98 From the drop down menu choose the material Berm Sand as shown in Figure 8 36 99 Click OK Layer 5 Material type Berm Sand Information on current material type Unit weight dry EN m3 19 50 Unit weight wet EM ma 21 00 Cancel Figure 8 36 Layer 5 properties window 8 9 3 Calculation and Results In order to start a calculation with this new geometry 100 Click Start from the Calculation menu to open the Start calculation window 101 Click OK 102 Choose Stresses from the Results menu to open the Critical Circle window This window shows that the minimum safety factor is now 1 35 instead of 1 10 without the berm The increase of the minimum safety factor as expected when adding a berm can also be seen in the Safety Ove
92. the following design methods Mean value analysis Calculation of the safety factor using fixed mean values of the parameters Design value analysis Calculation of the safety factor using fixed design values of the parameters D GEO STABILITY derives these unfavorable lower or upper limits from stochastic parameter distributions and partial factors Probabilistic design Calculation of the safety factor mean value a probability of failure and influence factors The probabilistic FORM First Order Reliability Method method uses varia tions of stochastic parameters for strength and pore pressure A system of probabilis tic defaults enables an approximate reliability analysis without any additional input of stochastic data The defaults are largely based on the Dutch NEN design standard D GEO STABILITY uses the defaults also to calculate approximate design values from mean values or approximate mean values from design values Probabilistic random field model The Bishop probabilistic random field model performs a probabilistic slope stability anal ysis in order to determine the probability that the safety factor is less than the required value Furthermore this model calculates sensitivity factors which are used by the computer program PCRING for the analysis of dike systems The computation model is based on Bishop s method of slices for equilibrium analysis random field modeling of spatial variability of soil strength and pore
93. the phreatic line is determined while the geometry is being defined If no phreatic line is entered then all the soil is assumed to be dry The phreatic line is also used to determine the water moment in the method of slices For all slices where the phreatic line is above the soil surface the load of the free water on the surface is taken into account as a moment around the slip circle centre V p water see Equation 16 3 Hydraulic pore pressure from piezometric level line A piezometric level line PL line represents the initial and transient hydraulic water head ex cluded the excess component A PL line can be defined for the top and the bottom of each soil layer Section 4 3 10 section 4 3 13 One of these PL lines can be defined as the phreatic line If no phreatic line or PL lines are defined then all the soil is assumed to be dry D GEO STABILITY calculates the hydraulic pore pressure along a vertical in the following way The pore pressure inside a layer is calculated by linear interpolation between the pore pressures at top and bottom The pore pressure at the top or bottom is equal to the vertical distance between this point and the position of the PL line that belongs to this layer multiplied by the unit weight of water See Equation 18 1 If PL line number 99 is specified for the top and or bottom of any soil layer D SETTLEMENT will use at that boundary the PL line of the nearest soil layer above or be
94. the shear strength values at other normal stress levels O l roe mus 20 11 O normal ref Note Stress tables are characterized by this one stochastic parameter whereas the c phi model is characterized by two Characteristic value from a normal distribution D GEO STABILITY determines a characteristic value of a normally distributed shear strength parameter x from the following equations Xcharac H ka Ucharac X Ctotal 20 12 P x lt Tora Oy narac 20 13 where u is the parameter of a standard normal distribution and Gtotai the value of the standard deviation D GEO STABILITY supplies defaults for the value of Ucharac per parameter type A probability P x lt Xcharac 0 05 corresponds for example to Ucharac 1 65 Characteristic value from a lognormal distribution D GEO STABILITY determines a characteristic value of a lognormal distributed shear strength parameter x by using the following equation Jcharac EXP u y Ucharac O lul 20 14 where u x u y iln EL 20 15 o ly vln 1 V 20 16 a Ototal 20 17 u x 242 of 264 Deltares 20 3 6 20 4 20 4 1 Reliability analysis Design value D GEO STABILITY determines the design value Zgesign Of a shear strength parameter x by using the following formula Tech Ldesign E 20 18 Tpartial where foartial is the partial factor used by D GEO STABILITY to reduce the characteristic strength to lower values D
95. to 2D stress the maximum shear stress Tmax is related to the difference in the two principal stresses c and o3 by the following equation Tmax 5 01 03 16 21 For a tensile test 04 o and o3 0 so that Tmax 10 16 22 Similarly the yield strength in shear 7 is related to the yield strength in tension 0 by Ty lg 16 23 2 01 0 Figure 16 7 Representation of the Tresca s criterion by Mohr s circle To represent this yield criterion graphically Mohr s circles are used Figure 16 7 It indicates that the yielding occurs if the radius of the Mohr s circle reaches 7 which writes H 10 lt P 1o 16 24 After integration of this equation over the cross section 5 of the nail the maximum shear stress criterion finally becomes AFS Fy lt EF 16 25 where Fy SX 9 is the yield force in tension as inputted in the Nail Type tab of the Nails window Figure 4 69 Soil nail normal reaction nail breaks in bending The plastification of the nail occurs for a limit shear force of Mama Fy Fo 1 62 is El 0 24 x p x Dx Lo 16 26 Lo F where Deltares 213 of 264 16 2 2 4 D GEO STABILITY User Manual D is the borehole diameter in m F is the yield force in tension as inputted in the Nail Type tab of the Nails window Figure 4 69 Du is the ultimate lateral stress see Equation 16 19 Lo is the reference length in m defined as TE Es Resisting
96. to the position that completes the new geometry as shown in Figure 7 12 3 112 of 264 Deltares 7 4 4 Graphical Geometry Input Figure 7 12 Modification of the shape of a berm Note When the Aad point s to boundary PL line button is clicked each left hand mouse click adds a new point to the nearest line until one of the other tool buttons is selected or click the right hand mouse button or press the Escape key Generate layers Use the Automatic regeneration of geometry on off button to start or stop the automatic conversion of construction elements to actual boundaries and layers Valid poly lines are converted to boundaries which are displayed as black lines Invalid lines remain blue Layers are generated between valid boundaries and default soil types are assigned It is possible to modify the soil type assigned to a layer by first selecting the layer and then clicking the right hand mouse button and choosing the Layer Properties option in the pop up menu to display the ayer window see Figure 7 21 in section 7 5 3 Once a material has been assigned to a layer this material will continue to be associated to that layer in subsequent conversions of construction elements as long as the layer is not affected by those conversions The most common cause of invalid poly lines is that they are not part of a continuous poly line running from limit to limit Sometimes lines appear to start end at a
97. use of predefined probabilistic parameters These are applied to soil strength parameters pore pressure properties and a model factor In order to modify these parameters 12 Click Probabilistic Defaults option in the Project menu The default values of the proba bilistic parameters are displayed in the window that opens Figure 13 4 In this tutorial the default values as provided should be used The defaults under Strength and Pore pressure are applied to all materials 13 Click OK 182 of 264 Deltares 13 4 Soil Probabilistic Defaults Strength Drained cohesion c Friction angle phi Strength fram stress table Ratio Lu Pc Undrained strength Cu State POP Pore pressure Consolidation coefficient 50 Hydraulic pressure Model Factor Limit value stability factor Bishop Limit value stability Factor Van Reset e KN fri H Coef of var Std dev maean 10 25 0 15 0 20 10 25 0 25 Coef of var Std dev mean IF 0 10 Tutorial 6 Reliability Analysis Design value factors Partial Std dev 1 25 LE 1 15 55 Design value factors Partial Std dev 1 10 11 65 Design value factors Partial Std dev 1 00 1 65 11 00 11 65 Std dev Distribution 0 08 Log normal Log normal 0 08 Distribution Log hormal Log normal Log normal Log normal Log normal Distribution
98. v Cancel Help Figure 8 21 Materials window 65 Enter the soil properties values of the four layers used in this tutorial Soft Clay Peat Sand and Berm Sand as indicated in Table 8 1 66 Click OK when finished Note It is possible to import soil properties from the MGeobase database see section 4 3 4 To this end MGeobase has to be installed Deltares 133 of 264 8 6 D GEO STABILITY User Manual See section 4 2 3 1 Materials Input of fixed parameters for a detailed description of this window Definitions In this tutorial D GEO STABILITY uses the Bishop method to determine the minimum safety fac tor for a soil structure by performing a slip plane calculation based on equilibrium of horizontal forces and moments D GEO STABILITY performs this Bishop calculation on several slip planes From those calculations D GEO STABILITY determines the slip plane with the lowest safety fac tor In D GEO STABILITY a slip plane is geometrically defined by its midpoint and by a tangent line In the Definitions menu specifications concerning such a calculation grid can be made by the user In addition possible tangent lines for each slip circle need to be defined This can be done manually or via the S ip Circle Definition window in the Definitions menu Figure 8 22 For the first method do the following 67 68 69 70 71 12 73 74 In the View Input window select the nput tab In the Edit toolbo
99. window to print the report Note Itis possible to export the report to a text file To do so click Export Active Window in the File menu The output file consists of the following elements general section program name and version update company name license and copy number title of the problem names of the used files echo of the input the safety factor table for each center point and for each tangent line and or fixed point section 6 1 1 information about the critical slip circle section 6 1 2 extensive information about the critical slip circle optional section 6 1 3 00002020 o The following sections describe the output in more detail The calculation process can be aborted after which a message is appended to the output file and the file is closed All results until the moment the calculation was aborted remain stored in the file Report Safety factor table long report If the Long report option is selected when starting a calculation section 5 2 a table with the X and Y coordinates of the center point the radius and the safety factor is presented for each calculated circle If the grid has moved during the calculation the new grid position is displayed followed by a new table with information on the circles and factors of safety for the new grid Messages may be displayed behind the safety factor column either indicating that the circle was rejected for some reason or noting anything exceptional about th
100. 0096 means no additional excess pore pressures See section 18 3 for background information 4 7 3 Earthquake The Earthquake Loads option in the Loads menu displays an input window in which a hor izontal and an additional vertical acceleration are defined For background information see section 17 3 Earthquake Degree af consolidation Horizontal earthquake factor a 3 000 E Vertical earthquake Factor a 1 500 Free water factor Cancel Help Figure 4 79 Earthquake window Horizontal earth Horizontal acceleration relative to gravity causing additional mo quake factor ment The direction of acceleration with positive sign is equal to the X direction Vertical earth Additional vertical acceleration relative to gravity causing temporary quake factor additional weight and moment The direction of acceleration with positive sign is equal to the direction of gravity The additional weight will also yield additional total vertical stress and additional hydraulic pore pressure Free Water Factor A reduction factor f on the moment caused by free water 0 lt f 1 default f 0 This factor can be used to simulate the drag down of free water by earthquake loading Degree of The relative degree of consolidation r per layer 0 lt r lt 100 default consolidation r 2 100 This is the relative amount of the total vertical stress by vertical earthquake loading that is assumed to be carried as effective vertical stress by the
101. 1 000 Edit AMI anal arena n dn nnn Pr i rna nnn rn nn nnn dn iaa viii ern nna Porn n n i rni nni rn n Fn rrt tiim Materials Dike sand E Dike sand 2 E Stiff clay E Peat EU Clayey sand Pleistoceen sand X 73 213 Figure 11 16 Stresses in Geometry window Tutorial 4a It can be seen that the pore pressures in the vertical have strongly alternating values from layer to layer This is due to the different degrees of consolidation that have been assigned to the layers New calculation adding slip planes Tutorial 4b Generate slip planes D GEO STABILITY has now calculated the safety factor for the dike using one defined slip plane However it is possible for D GEO STABILITY to determine the safety factors of the dike using a multitude of slip planes To create those slip planes the existing slip plane section 11 3 1 has to be enlarged and a second slip plane has to be first created D GEO STABILITY will create a number of slip planes based on these two slip planes The amount of which is determined by the amount of transversal grid points 44 Click Save as in the File menu and save this tutorial as lt Tutorial 4b gt 45 Click Save 46 Create a second slip plane by clicking the Add slip plane button Be sure that the Input tab of the View nput window is selected 47 Draw the second slip plane by placing points from left to right in the dike body It is im portant that the number of points is equal to that o
102. 1 3 Project Properties for a detailed description of this window Deltares 129 of 264 8 4 8 4 1 D GEO STABILITY User Manual Geometry In the Geometry menu the geometry aspects of the project can be specified Most of the rele vant geometry aspects of this tutorial have already been addressed in the Wizard section 8 2 With the Geometry menu it is possible to complete the geometry as given in Figure 8 1 In this tutorial the shape of the phreatic line needs to be modified and the piezometric level lines PL lines per layer need to be set After this has been done D GEO STABILITY can perform a check if all the entered geometry is correct Points At this point the phreatic level is still 4 0 m across the whole domain as set in the Wizard section 8 2 1 However according to Figure 8 1 the phreatic line has a curved shape with dif ferent water levels at both sides of the dike and a groundwater flow within the dike Therefore the phreatic line must be adjusted so that it represents the phreatic line of Figure 8 1 All lines in D GEO STABILITY are connections between points The phreatic line can be adjusted by creating new points or modifying existing points and connecting them to represent the phreatic line First the point on the right side of the boundary is lowered 44 Choose Points from the Geometry menu The Points window appears Figure 8 16 It is possible to modify the coordinates of the current points in the ent
103. 1 4 Report for Bishop Probabilistic Random Field model 94 62 Stresses in Geometry lll lll 95 6 3 Stresses 2o osos oos Rok EOS xo x xo 05 Nl 69 xoxo 9X s 96 6 3 1 Critical Circle Fellenius and Bishop 96 6 3 2 Critical Plane Uplift Van and Spencer 98 6 3 3 Critical Circle for Reliability Analysis 98 64 FMinGrid MMM lt lt 99 65 Safety Factor per Zone 2 2 2 100 66 Stresses per Zone lll lll 100 6 7 Influence Factors Mia Do 101 68 Safety Overview a e e e 102 Graphical Geometry Input 103 7 1 Geometrical objects 22er nn 103 7 1 1 Geometry elements cll ln 103 7 1 2 Construction elements 104 7 2 Assumptions and restrictions 104 7 3 View Input Window Wl a 104 7 3 General 2 oo n Ie 105 7 3 2 BMIBDS A 22 aaa a a 106 7 3 3 Legea g aaa a a 108 7 4 Geometry MOdAelng e 110 7 4 1 Create a new geometry eee 222r rn 111 ide SOUMI x s 30909 X AAA 111 7 4 3 Draw layout ociosa a 111 7 4 4 Generate layers o 113 7 4 5 Add piezometric level lines 114 7 5 Graphical manipulation a 114 7 5 1 Selection Of elements eee ee ee 114 7 5 2 Del
104. 1 FMin Grid window 9B et a 180 13 1 Geometry overview Tutorial 6 181 13 2 Model window Wh B a 182 13 3 Default Input Values window e 182 13 4 Probabilistic Defaults window 183 13 5 Materials window for Standard input 2 0002 ee ae 184 13 6 Materials window Shear Strength Advanced tab 185 13 7 Points window MY Mom Do 186 13 8 PL Lines window 2 ee a a 186 13 9 View Input window Geometry tab 187 13 10 External Water Levels window MHW 188 13 11 External Water Levels window MLW 189 13 12 Critical Circle window ooa 6 ee a 190 13 13 Critical Circle window for Mean High Water level 190 13 14 FMin Grid window 1 a a 191 13 15 Influence Factors window 192 14 1 Geometry overview Tutorial 7 aoa a oa a a a a a a 193 14 2 Model windORBIB LM 2222 o RR 194 14 3 Model Factor window a a a a 195 14 4 Critical Circle window llle 195 15 1 Geometry overview Tutorial 8 197 15 2 Model window noo ox X Xo x ox xk OX Wd 0 43x EE EGE 198 15 3 Zone Areas for Safety window 199 15 4 Materials window e 199 15 5 Safety Factor per Zone window 200 15 6 Critical Circle window for Zone
105. 11 2 3 Importing material properties from an MGeobase database 159 11 24 Materials 2 2 2 2 2 2 2 2525 25 5 160 11 25 PL lines per layer lll ls 162 vi Deltares Contents 11 2 6 Degree of Consolidation 163 11 2 7 WS 223 Bh ewe ERK ewe od meh eh eee 163 11 3 Calculation using one defined slip plane Tutorial 4a 164 11 3 1 Slipe Plane 2 223 ewe se ede ed Ee dw ew 164 11 3 2 Calculation and Results 0 0 0048 165 11 4 New calculation adding slip planes Tutorial 4b 167 11 4 1 Generate slip planes 167 11 4 2 Calculation and Results ccc rn 169 11 5 Uncontrained slip plane Tutorial Ac 169 11 5 4 Calculation and Results l c ll n 170 11 6 Conclusion cosido rss v m xoc 171 12 Tutorial 5 The Uplift Van model 173 12 1 Introduction to the case cler 173 12 2 Geometry Wizard 97 9 174 123 Model 04 eeu X sss 175 12 4 Soil materials f0M WI 175 12 5 Geometry aaa aa a MEA o o o ool Toss 176 12 5 1 Points 42W lt M occ LLL 176 12 5 2 PL lines Ba 29 ew ee 177 12 5 3 PL lines perLayers 0 0 2 0 000 ee ee eee 177 12 6 Definitions 4 amp ess 178 12 7 Calculatio
106. 2 1 6 Limitations When working with D GEO STABILITY the following limitations apply o D GEO STABILITY can automatically determine the position of a critical slip circle This search algorithm is accurate as long as O the distribution of center points and tangent lines is reasonably fine O the location of the initial trial grid will yield a slip circle at the right slope H the shape of the true slip surface does not deviate significantly from the assumed shape D GEO STABILITY discards the friction following from the horizontal stress component at the vertical slice interfaces D GEO STABILITY therefore assumes that the orientation of a slip surface is predominantly horizontally D GEO STABILITY assumes values for the total vertical stress that are estimated from the composed weight of a vertical column of soil and from the additional load spread The influence of load spread by a non horizontal soil surface is therefore not taken into account Application of D GEO STABILITY is allowed as long as the two dimensional plane strain assumption applies See also section 20 4 2 Assumptions and limitations of the Reliability module 1 7 Minimum System Requirements The following minimum system requirements are needed in order to run and install the D GEO STABILITY software either from CD or by downloading from the Deltares Systems website via MS Inter net Explorer Operating systems O Windows 2003 O Windows Vista O Wi
107. 33 Figure 4 52 PL lines per Layer window Note For the deepest soil layer no second PL line number is required For this layer a hydrostatic increase of the pore pressure is automatically assumed from the pore pressure at the top of the layer downwards The following values can be used as PL line numbers N 0 N 99 The number corresponds to one of the PL lines defined during the geom etry input Capillary water pressures are not used that is if a negative water pressure is calculated for a point above the phreatic line the water pressure in that point is defined as O Each point within the layer has a water pressure equal to O Define O for PL line at top of layer It is possible to have a number of overlying soil layers with a non hydrostatic pore pressure for example a number of layers consisting of cohesive soil In this case a large number of PL lines would have to be calculated one or two for each layer To avoid this D GEO STABILITY is able to interpolate across layer boundaries For layers with a non hydrostatic pore pressure 99 can be entered as the PL line number For this layer the interpolation will take place between the PL line belonging to the first soil layer above with a real PL line number and the PL line belonging to the first soil layer below with a real PL line number The first and the last soil layer must therefore always have a real PL line number Note A real PL line number is not equal to 99 W
108. 4 31 Spencer model e 1 4 2 Uplift Van model 487 1 4 3 Reliability based design methods 1 4 8 Product integration cll 15 History 4 x 1 6 Limitations 422W Bo 17 Minimum System Requirements 18 Definitions and Symbols 19 Getting Help 4BR Z9 LLL 110 GettingSupport NMAZ9 LL 111 Deltares a 1 12 Deltares Systems 22er 1 13 Rijkswaterstaat DWW a 1 14 On line software Citrix lr rrr 2 Getting Started 2 1 Starting D GeoStability o 2 2 Main Window 2 ll sl ll lee ees a 2 2 1 The mengpar W e WD oos 2 2 2 Theiconbar aaoo a a 223 VIEWING MD WM 2 2 4 Infobar A 2 1 1 aaa a a a 2 25 Titlepanel S Mme 1 a 2 2 6 GBP WM 22 o o n n n o n n n ng g 9 27nHaee 2 3 Fless9 WM O lllo nm 24 Tips and Tricks NM o 2 4 4 Keyboard shortcuts lll lll ln 2 4 Exporting figures and reports 2 4 8 Copying partofatable 0 2 44 Command line 3 General al PEME a 559 599 099 3 3 239 EE 3 2 5 5 32 Toob Meni uu uoo xo 9 x EX OER eee a xod x95 4 3 2 1 Program Options 2 2 2 2
109. 50 0 250 Cancel Help Figure 8 17 Pl Lines window 57 Click OK to confirm Note The phreatic line drawn in this example is a very crude approximation on the actual shape of the phreatic line It is possible to import a detailed and realistic shape of a phreatic line from calculations in MSeep or WATEX The PL line and thus the phreatic line have been changed and can now be seen in the View Input window Figure 8 18 Deltares 131 of 264 D GEO STABILITY User Manual w D an AAA N oS D a lo 4 TUTTE EEE X 62 250 Y 6 750 Edit Current object Point Figure 8 18 View Input window with new phreatic line See section 4 3 10 PL lines for a detailed description of this window 6 4 3 PL lines per layer Each soil layer has to be assigned its own piezometric level In the situation in this tutorial the water level in the reservoir is at its maximum design level If this water level is constant for a longer period of time it can be assumed that all the hydrostatic pressures in all the soil layers will be defined by the phreatic line Such a situation is assumed in this tutorial and thus all the layers have their piezometric level in the phreatic line In this case that is PL line number 1 To assign the phreatic line line 1 to be the PL line of each of the layers do the following 58 In the Geometry menu choose PL lines per layer to open the PL ines per Layer window 59 Enter PL line
110. 52252 252 25 5 5 Materials window for Pseudo values shear strength model with Global mea cing Ge oa Bo PTTTTELTTP Soil Groups window 6 6 6 we ll ll el Materials window for Standard stochastic input Xi D GEO STABILITY User Manual xii 4 32 4 33 4 34 4 35 4 36 4 37 4 38 4 39 4 40 4 41 4 42 4 43 4 44 4 45 4 46 4 47 4 48 4 49 4 50 4 51 4 52 4 53 4 54 4 55 4 56 4 57 4 58 4 59 4 60 4 61 4 62 4 63 4 64 4 65 4 66 4 67 4 68 4 69 4 70 4 71 4 72 4 73 4 74 4 75 4 76 4 77 4 78 4 79 4 80 5 1 Du 9 3 9 4 C phi Standard stochastic input eae 50 C phi Advanced stochastic input eae 50 Stress table sigma tau Standard stochastic input 51 Stress table sigma tau Advanced stochastic input 51 Cu calculated Standard stochastic input 51 Cu calculated Advanced stochastic input 52 Cu measured Standard stochastic input 4 53 Cu measured Advanced stochastic input 53 Cu gradient Standard stochastic input 4 54 Materials window for Bishop probabilistic random field method 54 Materials window for nails with option Use soil parameters c phi cu 56 Model Factor window 2 6 ee a 57 Import Geometry From window 2 2 2 2 2 58 Geometry Limi
111. 6 2 2 3 1 the tensile resistance at the soil nail interface is reached section 16 2 2 3 2 the soil fails in bearing below the nail section 16 2 2 3 3 the tensile and shear resistance of the nail is reached section 16 2 2 3 4 the stiff nail breaks in bending The vector Fra FN Fp must be located within the stability domain satisfying the four cri teria mentioned above The program determines the vector giving the maximum fy and the minimum Fp This is illustrated in Figure 16 6 where criteria 1 and 3 are relevant Criterium 1 Tensile resistance at soil nail interaction during pull out is fe Criterium 2 Soil fails in bearing below the nail Criterium 3 Tensile and shear resistance of the nail is reached Fp kN Criterium 4 Nail breaks in bending Figure 16 6 Representation of the four criteria in the Fy Fp diagram to determine Fhail Influence of the critical angle Depending on the value of angle between the nail and the tangent line along the circle where the nail intersects the slip circle compared to the value of the critical angle Qcritical inputted in the Nails window see Figure 4 71 FN or Fp can be neglected If lt Qceritica the shear force is neglected Fn min Ena Fy 16 12 fp 0 o If a gt 90 amica the lateral force is neglected where FN Fb 2 Pp F y Fy 0 16 13 F Fp min Foz Pi Foa is the limit resistance to pull out b
112. 64 D GEO STABILITY User Manual is in zone 1 see Figure 22 2 Polder Figure 22 2 Schematization of the modified slip surface deformed situation after rota tion The additional calculation makes the assumption that if the slip surface slides the stability factor changes The driving moment decreases whereas the resisting moment increases Because the ground will deform the sliding force of the ground decreases This decrease of the force is taken into account in the using a factor called remolding reduction factor Based on tests and literature the default value of this factor is set to 0 5 in D GEO STABILITY however it can be changed in the Calculation Options window section 5 1 Additional calculation is carried out as a supplement to the standard calculation It is assumed that the ground which is beyond the exit point after rotation and therefore above the surface level is no more part of the slip surface During the calculation of the stability of the sliding slip surface an extra model factor called schematization reduction factor is used Its default value is set to 0 8 but it can be changed in the Calculation Options window section 5 1 258 of 264 Deltares 23 Benchmarks Deltares Systems commitment to quality control and quality assurance has leaded them to develop a formal and extensive procedure to verify the correct working of all of their geotech nical engineering tools An extensive range of benchmark checks h
113. Basisveen Bt AL Basisveen Tau kr 0 0 20 0 40 0 80 0 20 0100 0 140 0 Sigma KN m DR Cancel Help Figure 4 14 Sigma Tau Curves window with imported data 4 2 1 2 Sigma Tau Curves for Reliability analysis If the Reliability analysis in the Model window is enabled section 4 1 1 D GEO STABILITY uses stochastic values for its calculations The values in the sigma tau relation are user defined It is possible that the user provides basic values or data that includes stochastic values If only deterministic values are provided while the Reliability analysis is enabled D GEO STABILITY automatically determines the stochastic values of the Sigma Tau curves It does so using standard stochastic assumptions given in the Probabilistic Defaults window section 4 1 2 In this case the stress table will consist of two additional columns Column 3 contains the characteristic value Column 4 contains the mean value See Figure 4 15 for an example 40 of 264 Deltares Sigma Tau Curves Curve name Curve 1 Btw AL Basisveen Ertl HOLLANDYVEER Tau Tau Sigma Tau Curve characteristic mean Kr Al HOLLANDVEEN NAAST kN r kN nF 5 ca a tu E Es a Sigma KN m Figure 4 15 Sigma Tau Curves window for Reliability Analysis 4 2 1 3 Sigma Tau Curves for Pseudo values Shear strength model If the Pseudo values shear strength model in the Model window is enabled section 4 1 1 D GEO STABILITY use
114. Clay organ weak Clay el zan moderate Clay sl san stiff Clay el zan weak Clay ve san stiff Dense Sand Gravel Gravel sl ail loose Gravel sl sil moderate Gravel sl sil stiff Gravel ve sil loose Gravel ve sil moderate Gravel ve sil stiff Loam Loam sl san moderate Loam sl san stiff Loam sl san Weak Loam ve san stiff Loose Sand Medium Clay Muck Peat Peat mad pl moderate Add Insert a Peat not pl weak Delete Rename sand P ne Cancel Help Figure 4 27 Materials window Database tab Import predefined soil types Maternal name Undetermined Clay clean stiff 46 of 264 Deltares Input Note lf the soil type has already been defined locally then D GEO STABILITY will ask if the existing local properties should be overwritten Information o Material name in use overwrite E Cancel Figure 4 28 Information window 4 2 3 3 Materials Soil Groups This option is available only if the Pseudo values shear strength model with Global measure ments in the Model window is enabled section 4 1 1 On the menu bar click Materials in the Soil menu see Figure 4 29 This window is the same as for fixed parameters section 4 2 3 1 except that it is now possible to define Soil Groups Inside a soil group correlation factors be tween the soil materials are used for the calculation of the pseudo Tau value For background information refer to section 19 4 2 Materials
115. D GEO STABILITY User Manual New Wizard Set material types Layer Mr Material Type 1 Sand 2 Peat r El Soft Clay Previaus 1 13 Set Layer Nr 1 to Sand 14 Set Layer Nr 2 to Peat 15 Set Layer Nr 3 to Soft Clay 16 Click Next 8 2 5 Wizard Checking Set all layers to material type Soft Clay Apply Show properties of material type Soft Clay Properties E Cancel Help Figure 8 6 New Wizard window Soil selection The last window of the Geometry Wizard Figure 8 7 presents an overview of the entered geometry The user can check whether it is as desired If not the Previous button can be used to modify the values in the previous Wizard windows 124 of 264 Deltares Tutorial 1 Dike reinforced with berm New Wizard Basic layout Limit Left rn Limit Right m Number of Layers Ground Level m NAF Phreatic Level m MAP Top laver hi m 5 00 L1 m 17 50 hZ m 200 L2 m 6 00 L3 m 10 00 L4 m 8 00 L5 m 3 00 Material types Layer 1 Sand Layer Peat Layer 3 Soft Clay Previous ini E Cancel Help Figure 8 7 New Wizard window Geometry overview 17 Click Finish 8 2 6 View Input A View Input window appears Figure 8 8 with the D GEO STABILITY geometry that has been created so far At this point the geometry needs to be saved 2 View Input c J inm Geometry Input Edit A E m Materials RO c UL sor clay
116. Deltares 87 of 264 4 4 D GEO STABILITY User Manual Uplift Spencer Note Some features like Fmin in grid don t work after a genetic algorithm based calculation Note It is possible to find only so called zone 1 circles using the genetic algorithm but one needs to take care when using this method One can do so by checking enable under zone plot in the model window This option gives a penalty of 3 to each zone 2 or zone 3 circle If a safety factor higher than 3 is returned chances exist no zone 1 circle is found The search space must be defined in the same way as by the grid based method The shown grid is not used instead the slip plane with the lowest resistance is found with the genetic algorithm A very large search area may be used with Bishop s method as the optimization technique Is very efficient This method is particularly useful with Spencer s method An upper and lower slip plane must be defined a grid based calculation is not possible with a significant number of transversal grid points and points along the slip plane as the number of possible combinations increases exponentially Only the genetic algorithm can find an unconstrained slip plane Click the Options button to open the Options Genetic Algorithm window and view the default options Figure 5 4 Those advances options are chosen automatically based on the chosen limit equilibrium method and the size of the search space If these def
117. Design value high water Number of iterations Alfas The final value of the reliability index 6 In case of a stochastic ex ternal water level this value is the result of the integration of the conditional values for the different water levels Only for a stochastic external water level the value of the water level corresponding to the integrated value of 5 Only for a stochastic external water level the number of iterations used for the determination of the integrated value The sensitivity coefficient of parameter x indicates the effect of parameter change and parameter uncertainty on the probability of failure for the cross section a zi du ja ole The sensitivity coefficients for soil parameters result from integration along all soil types The sum of the sensitivity coefficients equals 1 The values are based on a cross section analysis only Q 6 2 Stresses in Geometry The Stresses in Geometry option in the Results menu presents a view of the distribution of pore pressure and effective vertical stress along verticals that can be selected with the mouse pointer Clicking the cursor anywhere in the horizontal domain will produce a representation of the stresses in the vertical at that point It is also possible to manually provide the X coordinate in the domain of which to see the stresses in the vertical at that point This X coordinate can be given in the upper left corner of the screen Deltares
118. Dutch TAW guidelines TAW 1985 1989 1994 If a slip surface leaves intact this rest profile a lower required safety factor can be used zone 2 A third zone called zone 3 is also defined This zone contains all the slip surfaces which are important for the traffic function of the dike It is also determined if the action of the high water has an influence on the slip surface If it is the case then the slip surface is situated in zone A and a high required safety factor must be used If the action of the high water has no influence on the slip surface then a less strict required safety factor can be used in the zone B Determination of the modified slip surface A slip surface passing through zone 1 but with an entrance point in zone 2 is according to the zone plot method defined as a slip surface in zone 2 only if the modified slip surface deformed situation leaves the rest profile intact For this deformed situation an additional calculation is carried out The original entrance point of the slip surface is dropped down to come just in the rest profile The entrance point of this modified slip surface lies then in zone 1 and therefore must satisfied the required safety of zone 1 If the modified slip surface satisfies the required safety of zone 1 then the original slip surface non deformed situation is in zone 2 If the modified slip surface does not satisfy the required safety of zone 1 then the slip surface Deltares 25 of 2
119. EO STABILITY in PDF format Here help on a specific topic can be found by entering a specific word in the Find field of the PDF reader Getting Support Deltares Systems tools are supported by Deltares A group of 70 people in software develop ment ensures continuous research and development Support is provided by the developers and if necessary by the appropriate Deltares experts These experts can provide consultancy backup as well If problems are encountered the first step should be to consult the online Help at www deltaressystems com menu Software Different information about the program can be found on the left hand side of the window Figure 1 1 In Support Frequently asked questions are listed the most frequently asked technical questions and their answers In Support Known issues are listed the bugs of the program In Release notes are listed the differences between an old and a new version Deltares Areas of expertise Software Academy facilites Aboutus Contact Enabling Delta Life Zz D Geo Stability Features gt Support Modules gt Demo Screenshots gt Service packages gt Technical Specifications gt We are here to help you with all your Deltares software products and solutions Other related software gt Over the last decades Deltares has been developing and improving D Geo Stability which comes with everything a modelling professional needs in a flexible stable
120. Figure 4 4 Default Input Values window Zone plot Enable ing different safety factors in the dike body 4 1 2 Probabilistic Defaults Mark this check box to enable the usage of zone plot which allows defin On the menu bar click Project and then choose Probabilistic Defaults to open the input win dow This option is only available if Reliability Analysis has been selected in the Model window section 4 1 1 In this window the default settings for the uncertainty in soil parameters pore pressure parameters and in model factor Probabilistic Defaults Strength Drained cohesion c Friction angle phi Strength from stress table Ratio Cur Pe Undrained strength Cu State POP Pore pressure Consolidation coefficient 50 x Hydraulic pressure kNm Model factor Limit value stability factor Bishop Limit value stability Factor Van Reset 32 of 264 Coef of var 5td dev mean 0 25 Caef of var Std dew mean 10 10 Std dev Design value factors Partial Std dev 1 25 65 1 10 1 65 1 15 1 65 1 15 1 15 1 65 1 65 Design value factors Partial Std dev 1 10 1 65 Design value factors Partial Std dev 1 00 1 65 11 00 11 65 Std dev Distribution 0 08 Log normal Log normal 0 08 Distribution Log normal Log nomal Log normal Log hormal Log normal Distribut
121. Function A FORM analysis results in the reliability indexwhich iscalculated with the following equation u F required B 20 20 a F where u F is the expected mean value of the safety factor eS is the standard deviation of the safety factor In D GEO STABILITY the FORM analysis results are also used to determine so called influence factors per parameter The influence factor for parameter x is defined by OZ O Ea ETA Aa sor 20 21 2 n OZ Ya ted 22 The influence factor therefore reflects the sensitivity of the safety factor for the variation of pa rameters with significant uncertainty standard deviation Reduction of the standard deviation will reduce the value of the influence factor Assumptions and limitations of the Reliability module D GEO STABILITY can model the shear strength parameters and the pore pressures as stochastic data The uncertainty in geometry unit weight and loads is not directly taken into account Spatial variability can only be modeled explicitly by using the Bishop probabilistic ran dom field module formerly Known as the MProStab module The Reliability analysis module of D GEO STABILITY assumes homogeneous soil parameters Out of plane effects can only be modeled with the Bishop probabilistic random field module The Reliability analysis module does not model the out of plane effects The probabilistic FORM procedure is available in combination with the Bishop mod
122. Geometry 2 00 2 eee ee ee 137 8 8 3 Stresses Om o 138 8 84 FMinGrid gmm WM 140 8 8 5 Safety Overview 141 89 Berm construction W ZEE aa 142 8 9 1 Berm inputted graphically 142 8 9 2 Soil material assigned to the berm 144 8 9 3 Calculation and Results 0224s 144 8 10 Conclusion BY Mm ee ee ee 145 9 Tutorial 2 Unsaturated soil 147 9 1 Introduction to the case 2 a a lll rr 147 9 2 Project Properties lll llle 147 9 3 Changing the phreaticline 148 9 4 Soil properties ie WM es 150 9 5 Definitiggg MB s o ee RR 150 9 6 Calculation and Results lll a 151 9 7 Conc ea 6 OR o o o9 ooo ED o9 o ook we ee xs 152 10 Tutorial 3 Geotextile 153 10 1 Introduction to the case lll lll 153 10 2 Project Properties 02 E 2 22 154 10 3 Geotextile a lll llle 154 10 4 Calculation and Results lll rrr a 156 10 5 CODCIUSIOM c s s e ew x Boe dece ck OE ke ee OR om o x OR oos oos 156 11 Tutorial 4 The Spencer Method 157 11 1 Introduction to the case lll lll 157 TELS PINE ez xx x mcm WoW woE ww XE Nw woX dk Oe eee ee eS 158 11 2 1 Importing an existing geometry 158 TREE BEEN 3 20x 9 WLE ROS OR rasa 159
123. Graphical representation of the zone areas of the Zone plot model 0 the bold red line represents the rest profile H the vertical and horizontal dotted black lines represent the boundaries of the de sign level influence respectively at X and Y H the two inclined dotted black lines at the right side of the window represent the limits of the minimal road influence 100 of 264 Deltares 6 7 View Results Xm 46 43 m Radius 11 36 m Ym 7 71 m Safety 1 10 m 51 954 v 12 065 Edit Figure 6 11 Critical circle window for the Zone plot model For the description of the Mode panel refer to section 6 3 Influence Factors In case of a probabilistic analysis the nfluence factor option in the Results menu gives access to the nfluence Factors window This window shows the influence of variations of uncertain parameters on the probability of failure see Equation 20 21 page 293 When using external water levels section 4 6 2 for probabilistic design it is possible to view the results for each level separately by using the selection list on top Besides the results for each level it is also possible to view the integrated influence factors calculated by D GEO STABILITY in the design point Figure 6 12 Influence Factors window Deltares 101 of 264 6 8 D GEO STABILITY User Manual Safety Overview The Safe
124. M First Order Reliability Method supplies a reasonable balance between the accuracy required and the efficiency desired Result of a probabilistic analysis is the reliability index D D GEO STABILITY support both these approaches beside the traditional mean value analysis Stochastic distributions In order to support a First Order Reliability Method calculation D GEO STABILITY can apply a standard normal or lognormal probability distribution for all stochastic parameters Both distribution types are characterized by a mean u and a standard deviation o for a standard normal distribution Normal distribution The probability that a value x is smaller than the value Zcharac is for a normal distribution expressed by charac P x lt c by arac J QN u x du 20 1 where u is the parameter of a standard normal distribution u EE O v Ucharac is the integral of the standard normal probability density xp u 2 oN u is the standard normal probability density yy u C Deltares 239 of 264 20 3 20 3 1 20 3 2 D GEO STABILITY User Manual Lognormal distribution If parameter y ln x has a normal distribution then parameter x has a lognormal dis tribution A lognormal distribution always yields positive values The normal and lognor mal distributions are similar for small ratios between the standard deviation and the mean D GEO STABILITY uses Equation 20 2 and Equation 20 3 respectively to calculate u
125. Options Genetic Algorithm window and view the de fault options Figure 11 21 Those advances options are chosen automatically based on the chosen limit equilibrium method and the size of the search space If these defaults do not lead to the desired optimum the advanced options must be set differently Some knowledge of genetic algorithms is required in order to do this Options Genetic Algorithm Population Population count Generation count Flite count Mutation rate CrossOver method Fraction Scatter Single Point Double Point Mutation method Jump Creep Inverse 0 000 0 700 0 300 Fraction 0 000 0 300 0 100 Creep Reduction 0 050 Cancel Help Figure 11 21 Options Genetic Algorithm window Tutorial 4c 60 Leave the values to their defaults and click OK to close the window Note Having a unnecessarily large search space decreases the precision of the answer This 170 of 264 Deltares 11 6 Tutorial 4 The Spencer Method can be compensated by increasing the size of the population and the number of generations but it increases the computational time Note The optimization parameters are calculated based on the limit equilibrium method and the size of the search space These defaults do not always guarantee al global minimum with sufficient accuracy With a little knowledge of genetic algorithms the user can change the calculation options but a c
126. Shear Strength models In D GEO STABILITY Equation 19 5 is implemented using the following formula F Tij pmeas a u r Pj r 19 6 22 char With OT ms Tij char where p P is the pseudo characteristic factor for layer 7 P A Y 4 1 T isthe total shear stress in layer T 7 lij X m Global measurements regional set of tests In case of global measurements from a regional set of in situ tests the variances of the contributions to the total shear stress which come from separate ground layers which are not associated with another ground layer can be calculated using equations of section 19 4 1 Note In D GEO STABILITY two associated layers are part of the same soil group For more information about the Soil Groups option refer to section 4 2 3 3 For the variances of the contributions of associated ground layers the combined contribution of two associated ground layers must be considered Assuming that layers 7 and k are asso ciated for example 7 is the layer under the dike and k is the corresponding layer beside the dike the combined contribution to the total shear stress along the slip circle is E Nk Lin Y lj X Tij t N dy X Thk 19 7 i 1 h 1 The variance of this contribution is 2 neg Nk c Tye E X 105 Y Tae One 19 8 i l h 1 This equation leads to o Tik 0 T o Tx 2Rg x c T x o Tx 19 9 c T is the standard devi
127. Tp Pre consolidation stress also written P Slices b Width of slice h Height of slice 2 k Number of layers along slice 2 l Length of the arc at bottom of slice i l b cos a n Total number of slices in which the sliding part of the ground mass is divided Nett Number of slices in which the left sliding part of the ground mass is divided Uplift Van Nright Number of slices in which the right sliding part of the ground mass is divided Uplift Van A stop Horizontal coordinate of the middle top of slice 2 isbottom Horizontal coordinate of the middle bottom of slice 2 i top Vertical coordinate of the middle top of slice 2 i bottom Vertical coordinate of the middle bottom of slice Qi Slide plane angle at the bottom of slice 2 7 of 264 D GEO STABILITY User Manual Bi Slope angle at the top of slice 2 Stresses acting on a slice u Uh O Q T Hydraulic piezometric pore pressure Hydrostatic pore pressure from the position of the phreatic line Total vertical soil stress positive in compression Effective vertical soil stress positive in compression Shear stress Slip plane Slipe circle s The factor of safety R The radius of the slip circle Bishop Fellenius Rett The radius of the left slip circle Uplift Van Right The radius of the right slip circle Uplift Van The X coordinate of the slip circle Bishop Fellenius A cleft The X coordinate of the left slip circle Uplift Van A ex
128. Use the Properties option in the Project menu to adjust the grid distance and force the use of the grid by activating Snap to grid section 4 1 3 When this option is activated each point is automatically positioned at the nearest grid point The specified line pieces must form a continuous line along the full horizontal width of the model This does not mean that each line piece has to be connected exactly to its predecessor and or its successor Intersecting line pieces are also allowed as shown in the examples of Figure 7 11 Lo 1 2 3 Figure 7 11 Examples of configurations of poly lines Configuration 1 is allowed The different lines are connected and run from boundary to boundary Configuration 2 is also allowed The different are connected They are defined as being connected because they intersect The line construction runs from boundary to boundary Configuration 3 is illegal as there is no connection with the left boundary Add point s to boundary PL line Use this button to add extra points to lines lines polylines boundary lines PL lines By adding a point to a line the existing line is split into two new lines This provides more freedom when modifying the geometry For example the shape of the berm of Figure 7 12 1 needs to be modified Two points are added to the outer lines of the berm as shown in Figure 7 12 2 Then the middle point is selected and dragged
129. Vert tot var phi Input Standard deviation of the cohesion otandard deviation of the tangent of the friction angle Correlation coefficient between cohesion and friction angle ranging be tween 1 and 1 A1 A zero value means that parameter values can vary independently A value of 1 means that the values of cohesion and fric tion vary identically on normalized scale A value of 1 means that the increase of one value causes an identical decrease in the other value again on normalized scale otandard deviation of the hydraulic pore pressure per material This hy draulic pressure is derived from the input of PL lines per layer Geometry menu Water menu See section 20 4 3 Bishop prob random field correlation length of the cohesion See sec tion 21 5 1 Equation 21 3 The vertical correlation length of the cohesion See section 21 5 1 Equation 21 3 Number of tests used to determine the cohesion The model uses this value to modify the auto correlation function See section 21 5 1 Equa tion 21 5 The ratio between vertical and total variance variance is the square of the standard deviation of the cohesion See section 21 5 1 Equa tion 21 3 The horizontal correlation length of the friction angle See section 21 5 1 Equation 21 2 The vertical correlation length of the friction angle See section 21 5 1 Equation 21 2 Number of tests used to determine the friction angle The model uses this value to modify the auto co
130. a a Project Properties window Identification tab Project Properties window View Input tab Project Properties window Stresses Results tab Project Properties window FMin Grid Results tab Project Properties window Safety Results tab Project Properties window General tab ee Sigma Tau Curves window for deterministic design Import Stress Table window 2l lll Sigma Tau Curves window with imported data Sigma Tau Curves window for Reliability Analysis Sigma Tau Curves window for Pseudo values shear strength model Bond Stress Diagrams window a a a a a a Import Stress Table window 2l ll ln Bond Stress Diagrams window with imported data Materials window for fixed value input n Materials window C phi shear strength model Materials window Stress Tables shear strength model Materials window Cu Calculated shear strength model Materials window Cu Measured shear strength model Materials window Cu gradient shear strength model Program Options window Locations tab Database selection Materials window Database tab Import predefined soil types Information window 2 2 2 2 2 2 22 2
131. ab seen here in Figure 4 50 to define the boundaries for all layers by choosing the points that identify each boundary Layers Boundaries Materials Boundaries Add Insert Delete Cancel Help Figure 4 50 Layers window Boundaries tab On the left hand side of the window it is possible to add insert delete or select a boundary In the table on the right it is possible to modify or add the points that identify the selected boundary Note It is only possible to select points that are not attached to PL lines section 4 3 10 Note It is only possible to manipulate the Point number column because the coordinate columns are purely for informative purposes To manipulate the coordinates of the points select the Points option in the Geometry menu see section 4 3 8 Note When inserting or adding a boundary all points of the previous boundary if this exists 62 of 264 Deltares 4 3 13 Input are automatically copied By default the material of a new layer is set equal to the material of the existing layer just beneath it The Materials tab see Figure 4 51 enables the user to assign materials to the layers Layers Boundaries Materials Available materials Layers Number Mateatname B a dike sand stiff clay Peat clayey sand pleistoceen sand dike sand Figure 4 51 Layers window Materials tab On the left of the screen a list containing all defined materials s
132. al Conclusion It is possible to describe the shear strength properties of a soil with different models One of those models is the undrained shear strength In this tutorial a case in which it is relevant to use this model has been presented 152 of 264 Deltares 10 Tutorial 3 Geotextile 10 1 This example continues the case in Tutorial 1 chapter 8 The same soil structure is in place and the same layer build up is present Now the effect of the presence of a geotextile placed in the geometry is considered The objective of this exercise is To learn how to place a geotextile into the geometry For this example the following D GEO STABILITY module is needed D GEO STABILITY Standard module Bishop and Fellenius This tutorial is presented in the file Tutorial 2 sti Introduction to the case In the geometry presented in Tutorial 1 the influence the placement of a geotextile has on the safety factor is assessed see Figure 10 1 Using a geotextile placed between two soil layers can help improve the stability of a slope When a geotextile intersects the critical slip circle it helps to enlarge the resisting moment and increase the safety factor The contribution to the resisting moment increases when the tensile strength of the geotextile is of a greater value The characteristics of the geotextile are given in Table 10 1 The reduction area is set at a low value in order to make sure that the full tensile strength of the ge
133. am E Cancel Help Figure 3 6 Program Options window Modules tab For a D GEO STABILITY installation based on floating licenses the Modules tab can be used to claim a license for the particular modules that are to be used lf the Show at start of program check box is marked then this window will always be shown at start up For a D GEO STABILITY installation based on a license dongle the Modules tab will just show the modules that may be used Help menu The Help menu allows access to different options Error Messages If errors are found in the input no calculation can be performed and D GEO STABILITY opens the Error Messages window displaying more details about the error s Those errors must be corrected before performing a new calculation To view those error messages select the Error Messages option from the Help menu They are also written in the err file They will be overwritten the next time a calculation is started Deltares 2 of 264 3 3 2 3 3 3 3 3 4 3 3 5 D GEO STABILITY User Manual 9 Error Messages Lo JLo Ja FILE C Users rtd Desktop Tutorieal la err DATE 5 27 2014 TIME 3 30 46 PM E ERRORS IN SLIP CIRCLE DEFINITION Number of slip circles 0 is outside its limits 1 10000000 de e e dede de de dede de de de de de de de de he de de de e dede de de de de he d de de de d de de he de de de e de de de e de du de de du de de d de du e du de de d du de he de de de e de du de e d
134. ancel Help Figure 4 9 Project Properties window FMin Grid Results tab Info bar Mark this check box to display the information bar at the bottom of the FMin Grid results window Rulers Mark this check box to display the rulers Same scale for Mark this check box to enforce the same length scale for horizontal and x and y axis vertical axis Large cursor Points Iso lines Number of lines Minimum value Maximum value Use values from results Display line numbers Mark this check box to use the large cursor instead of the small one Mark this check box to display geometry points Mark this check box to display iso lines of the safety factor on the grid of center points Define the number of iso lines between the lower and upper limits Define the lower limit of the iso lines to be displayed Define the upper limit of the iso lines to be displayed Mark this check box if iso lines should be displayed with the specified range and number Mark this check box to display the line numbers Project Properties Safety Results The Safety Results tab allows selecting the way the data in the Safety Overview results win dow is presented In this window the safety factor distribution is drawn in the geometry 36 of 264 Deltares Input Project Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Save as default Labels Display jw Rulers jw Origin Paints Iw
135. ar strength model Deltares 45 of 264 D GEO STABILITY User Manual Cu top The apparent undrained strength s at the top of the layer Cu gradient The apparent gradient in undrained strength s over the depth of the layer per meter 4 2 3 2 Materials Import from Database It is possible to access the MGeobase material database for predefined material properties It is necessary that the database option for D GEO STABILITY is available To be able to access the database its directory first has to be indicated in the Program Options window from the Tools menu Click on the Locations tab Make sure that the Use MGeobase database check box is marked The Browse button allows the user to determine the database file to be used Select the relevant database An example is given in Figure 4 26 V Use MGeobase database MGeobase database NAMBeobaseAD atabase mdb E Figure 4 26 Program Options window Locations tab Database selection To use the MGeobase database in the Materials option in the Soi menu do the following o On the menu bar click Soil and then select Materials in order to open the Materials window see section 4 2 3 1 Select the Database tab Select the material of which the properties are to be imported Click the arrow lt I button to import Materials Parameters Database Materials s Clay clean moderate Clay clean stiff Clay clean weak Clay organ moderate
136. ary 1 2008 GeoDelft together with parts of Rijkswaterstaat DWW RIKZ and RIZA WL Delft Hydraulics and a part of TNO Built Environment and Geosciences are form ing the Deltares Institute a new and independent institute for applied research and special ist advice Founded in 1934 GeoDelft was one of the world s most renowned institutes for geotechnical and environmental research As a Dutch national Grand Technological Institute GTI Deltares role is to obtain generate and disseminate geotechnical know how The in stitute is an international leader in research and consultancy into the behavior of soft soils sand clay and peat and management of the geo ecological consequences which arise from these activities Again and again subsoil related uncertainties and risks appear to be the key 10 of 264 Deltares General Information factors in civil engineering risk management Having the processes to manage these uncer tainties makes Deltares the obvious Partner in risk management for all parties involved in the civil and environmental construction sector Deltares teams are continually working on new mechanisms applications and concepts to facilitate the risk management process the most recent of which is the launch of the concept GeoQ into the geotechnical sector For more information on Deltares visit the Deltares website www deltares nl Deltares Systems Deltares objective is to convert Deltares knowledge into practical geo e
137. as been developed by Deltares About the Bishop probabilistic random field The Bishop probabilistic random field model performs a probabilistic slope stability analysis in order to determine the probability that the safety factor is less than the required value Furthermore this model calculates sensitivity factors which are used by the computer pro gram PCRING for the analysis of dike systems The computation model is based on Bishop s method of slices for equilibrium analysis random field modeling of spatial variability of soil strength and pore pressures and first order second moment probabilistic reliability analysis The probability of the external water level can be taken into account optionally Contribu tions to the failure resisting moment from the edges of a finite width cylindrical failure model Van Marcke 1983 can also be taken into account optionally History The original MProStab program has been developed since 1980 by GeoDelft with major sponsorship of the Dutch Ministry of Transport Public Works and Water Management Rijk swaterstaat The first DOS based release from April 1990 contained already almost all of the current func tionality The option for probabilistic external water levels was added in the extended version from November 2000 MProStab has been incorporated in the windows based D GEO STABILITY program version 9 8 in the course of 2003 and is now called the Bishop probabilistic random field model In t
138. ater pressures above the phreatic line are set to zero An example can be seen in Figure 4 53 D GEO STABILITY has a special input option if a PL line number 99 is given for the top and or bottom of any soil layer the nearest soil layer with thickness gt 0 0 meter0 0 meter and with a PL line number unequal to 99 above and or below the point is searched for In this layer the pore pressure is calculated Using this pressure together with the corresponding vertical co ordinate the pore pressure along the slip circle arc is calculated by interpolation If the interpolation point is located above the phreatic line the pore pressure is assumed to be zero or a negative capillary pressure depending on the sign of the given PL line number An example using two different PL lines is given in Figure 4 53 showing how the pore pressure varies in the vertical 64 of 264 Deltares PL line 1 K Input PL line 2 SAND CLAY SAND 2 1 99 1 SAND Figure 4 53 PL lines and vertical pressure distribution 4 3 14 Check Geometry Select this option to verify the validity of the geometry All requirements are checked If the geometry complies with all the requirements a message will confirm this see Figure 4 54 Information EM Figure 4 54 Information window on confirmation of a valid geometry If any errors are encountered during this check they are displayed in a separate window r Warning lt a
139. ation of the shear stress in layer 7 o T 72 li x 0 ni o T is the standard deviation of the shear stress in layer k o Ty 30 lag X O The NI is the number of layers that are cut by the slip circle n is the number of slices in layer 7 The separate characteristic factors and x for layers 7 and k are determined using the same procedure as for unassociated layers section 19 4 1 Difference is that a correlation Deltares 23 of 264 D GEO STABILITY User Manual factor Rjg between the two layers is now introduced c T5 Rix x 0 Ti CO X 19 10 db o Tix Rir x o 15 0 Til o E TS 19 11 l o Tia where Cik is the pseudo characteristic factor of the soil group containing layers 7 and k bb is the correlation factor between the associated layers 7 and k IE e 1 1 I N r N I factor set equal to I 0 25 according to the Dutch guideline for river dyke TAW N Nk are the number of tests performed in the regional set of tests of layers 7 and k The pseudo measured value for the shear stress at the bottom of slice 2 in layer 7 is deter mined using the same equation as for unassociated layers section 19 4 1 Tjj Tij pmeas T u Es 1 656 X O d 19 12 19 In D GEO STABILITY Equation 19 12 is implemented using the following formula Tjj Tij ipmeas DHT u a m Ps ofan X 07 19 13 Tij char with OT p Ems Tij char P oo Pir Xx RR x Pe P Pg
140. ault Mean W Use probabilistic defaults Advanced Horizontal undrained strength Cu 0155 Mean Top kNAm 6 00 337 Bottom kNA amp 00 Jas Figure 4 38 Cu measured Standard stochastic input Horizontal undrained Undrained shear strength for a horizontal slip plane derived from strength Cu DSS Direct Simple Shear DSS tests section 19 2 Top The apparent undrained cohesion s at the top of the layer Bottom The apparent undrained cohesion s at the bottom of the layer Std dev The value of the standard normal parameter Ucharac used by D GEO STABILITY to calculate the unfavorable characteristic value of the undrained shear strength section 20 3 4 section 20 3 5 Shear strength model Cu measured r Standard Shear strength input Default Mean W Use probabilistic defaults f Advanced Shear Strength Shear Strength Advanced Pore Fressure Uniform Cu Passive undralned strength Cu low TE Mean Top kiere 600 337 0 Bottom knare 8 00 45 5 Active undrained strength Cu high TC Mean Top kNAw r00 asa Bottom Ktm 900 SB Cu design value factors 1 15 Figure 4 39 Cu measured Advanced stochastic input Uniform Cu Select this option to define stress induced anisotropy for over consolidated soil section 19 2 Passive undrained The low value of the undrained shear strength at the passive side strength Cu low TE ofthe slip plane
141. aults do not lead to the desired optimum the advanced options must be set differently Some knowledge of genetic algorithms is required in order to do this Options Genetic Algorithm Population Population count Generation count Elite count Mutation rate CrossOver method Fraction Scatter 11 000 Single Point 10 000 Double Point 10 000 Mutation method Fraction Jump 11 000 Creep 0 000 Inverse 10 000 Creep Reduction 0 050 Cancel Help Figure 5 4 Options Genetic Algorithm window 88 of 264 Deltares 5 3 5 4 Calculations Population The product of the population and the generation count determines the precision of the calculation result A larger elite can increase the convergence speed but increases the risk of finding a local mini mum A different mutation rate can change the convergence speed and the smoothness of the solution CrossOver method Scatter implies a random combination of genes from both parents This fraction can be 100 in case of a relatively simple solution space like Bishop or Uplift Van With Spencer s method the slip planes become too chaotic and single or double point crossover will result in much better convergence Mutation method A jump mutation causes a gene to get another uniformly drawn value between the boundary conditions of the value A creep mu tation draws another value in a smaller range the change will be no more than the c
142. ave been developed to check the correct functioning of each tool During product development these checks are run on a regular basis to verify the improved product These benchmark checks are provided in the following sections to allow the users to overview the checking procedure and verify for themselves the correct functioning of D GEO STABILITY The benchmarks for Deltares Systems are subdivided into five separate groups as described below Group 1 Benchmarks from literature exact solution Simple benchmarks for which an exact analytical result is available Group 2 Benchmarks from literature approximate solution More complex benchmarks described in literature for which an approximate solution is known Group 3 Benchmarks for additional options Benchmarks which test program features specific to the program being verified o Group 4 Benchmarks generated with D GEO STABILITY The benchmarks in this chapter have no exact solution but are compared with other programs using the same method Group 5 Benchmarks compared with other programs The benchmarks in this chapter have no exact solution but are compared with other programs using the same method The number of benchmarks in group 1 will probably remain the same in the future The reason for this is that they are very simple using only the most basic features of the program The number of benchmarks in group 2 may grow in the future The benchmarks in thi
143. ave several local minimums in the grid Therefore when using a smaller grid it is possible to find one of the minimums With some experience however it is possible to make a good first estimate of the position of the center point of the critical slip circle and choose a reasonable grid around that estimate Care needs to be taken when the grid is moved several times automatically In that case the grid may move in such a way that ultimately micro stability is being calculated Micro stability is the safety factor of a very small slice out of the soil structure typically only a few centimeters deep If this is not desired automatic movement of the grid should be stopped 216 of 264 Deltares 16 3 Method of slices Uplift Van High pore pressures at the horizontal interface of weak layers with an underlying sand layer will cause reduction or even complete loss of shear resistance at this plane This can yield an uplift failure mechanism which is schematically drawn in Figure 16 9 RIVER SIDE a ACTIVE ZONE PASSIVE ZONE al p HORIZONTALLY COMPRESSED POLDER SIDE Figure 16 9 Uplift failure mechanism The passive side of the slip plane is elongated in order to find equilibrium of horizontal forces Van s method therefore assumes that the total slip plane is composed of a horizontal part bounded by two circular parts The safety factor is determined using equilibrium of the hori zontal forces acting on the com
144. bobox selected from the list of the last nine folders used for processing or looked up using the Browse button If the option Include subfolders is on all subfolders will be processed recursive Start Batch Calculation C Users Public Include subfolders OF Cancel Help Figure 2 7 D Geo Stability batch processing window When the second parameter is given e g C Program Files Deltares DGeoStability DGeoStability exe b D tmp DGeoStabilityBatch lt Filename only this file will be processed When the second parameter is a folder this folder will be processed including all recursive subfolders Plot The command line parameter plot is available in D GEO STABILITY When processing large amounts of calculations using this parameter enables you to create plots of every calculation during processing A wmf picture is exported of the critical circle or the 2 zone circles in case of zoneplot of every calculation E g C Program Files Deltares DGeoStability DGeoStability exe b Plot Filename gives the critical circle of the chosen file For this parameter the same second parameter rules apply as described in the previous paragraph Deltares 21 of 264 D GEO STABILITY User Manual 22 of 264 Deltares 3 General This part of the manual contains a detailed description of the available menu options for inputting data for a soil structure calculating slope stability and viewing results The examples in th
145. by default the direct input of undrained cohesion at the top and the bottom of a layer Cu gradient Use by default the input of the undrained cohesion at the top of the layer and the gradient over the depth of the layer Pseudo values Use by default the input of Sigma Tau curves based on in situ measure ments This button is available only with the Pseudo values shear strength _ Mesuemens model When clicking this button the Measurements window appears Figure 4 3 in which the type of inputted measurements used with the Pseudo values model can be defined Local for measurements resulting of laboratory tests performed on soil samples from the surrounding area where the stability analysis is per formed Global for measurements from a set of tests Measurements Local ooo Global Cancel Help Figure 4 3 Measurements window It is possible to change the choice of shear strength description per soil type via the Soil menu section 4 2 Reliability Analysis Enable Mark this check box to enable the usage of reliability based design chap ter 20 This option can be used only in combination with Bishop and Uplift Van models When clicking this button the Default Input Values window appears Fig Des Input Values ure 4 4 in which the type of input parameters either mean values or design values can be chosen Deltares 31 of 264 D GEO STABILITY User Manual Default Input Values Cancel Help
146. ce of such stretch is therefore a necessary though not sufficient condition for failure Whether or not real failure occurs de pends on the contribution to the resisting moment which comes from shearing forces at the edges of the finite width failure mode Calle 1985 The probability of occurrence of a stretch where the Bishop safety factor is less than 1 0 will be referred to as the probability of a potential failure zone The probability of failure taking the edge contributions to the failure resisting moment into account will be referred to as the probability of slope failure Probabilistic analysis The Bishop probabilistic random field module determines the probability of failure for one water level in two steps i e Cross Section analysis First order second moment probabilistic FOSM analysis of the slip circle equilibrium ac cording to Bishop s method The Bishop probabilistic model determines probabilities by lin earization of the limit state function at the mean value and at the so called design point value 254 of 264 Deltares Bishop probabilistic random field The latter approach is also known as the FORM method Based on input data regarding ge ometry and soil parameters and statistical data regarding soil strength parameters and pore pressures as previously discussed the computer program calculates statistical parameters of the Bishop stability factor The calculated parameters are the mean expected value upr th
147. ch procedure of the critical slip plane If the option Maximum X entree used is enabled enter a maximum X coordinate for the entry point of the slip plane On the Menu bar click Calculation and then chooseStart to open the Start window Fig ure 5 2 in which some settings can be adjusted before the start of the calculation Two optimization techniques are available to find the representative slip surface section 5 2 1 The grid method calculates all combinations of center points and tangent lines section 5 2 2 The genetic algorithm is an advanced optimization procedure that can find either the representative slip circle with Bishops or Vans method or an unconstrained slip plane using Spencer s method The genetic algorithm is a generally accepted opti mization method Default values are sufficient for most problems to converge In specific cases advanced options need to be adjusted Sufficient literature on this algorithm is available to understand the parameters used 5 2 1 Grid based calculation By clicking OK the calculation is started If the input contains no errors the calculation is started If the input data contains any errors a message is displayed 86 of 264 Deltares Calculations Start Search method Iw Move grid f Genetic algorithm Display Report Me Graphic indicator e Short report Long repart Calculation type Deterministic with mean values Deterministic with design values
148. ck Open in the File menu 2 Select Tutorial 1b 3 Click Open Deltares 147 of 264 9 3 D GEO STABILITY User Manual Click Save As in the File menu Enter Tutorial 2 as a file name Click Save On the menu bar click Project and then choose Properties to open the Project Properties window 8 Fill in Tutorial 2 for D GEO STABILITY gt and Unsaturated soil for Title 1 and Title 2 respectively in the dentification tab 9 Click OK NOOA Changing the phreatic line To lower the water level the phreatic line needs to be altered This can be done in the Geometry tab of the View Input window 10 Click the Add point s to boundary PL line button to create extra points on the current phreatic line 11 Place three points on the left part of the phreatic line by clicking three times between points 20 and 21 from left to right Points 25 26 and 27 should appear consecutively as shown in Figure 9 2 x 66 750 Y 9 000 Edit Current object None Figure 9 2 View Input window Geometry tab Adding of three points on the phreatic line 12 Click the Edit button to exit the Add point mode The coordinates of the first six points of the phreatic line have to be adjusted so that it repre sents the shape of Figure 9 1 The new points positions of Table 9 1 give an approximation of the desired shape To alter the phreatic line follow these steps 13 Select the first left point poi
149. ck are displayed in a separate window Of course it is always possible to close the window using the Cancel button but this will discard all changes 60 of 264 Deltares 4 3 9 4 3 10 Input Import PL line Use this option to display the mport PL line dialog for importing a Piezometric Level PL line from an existing MPL file Such file is made using the WATEX program of Deltares in tab Head Location Plot click on the button Export and fill in a file name in the Export Water Pressure Line window PL lines Use this option to add or edit Piezometric Level lines PL lines to be used in the geometry A PL line represents the pore pressures in the soil A file can contain more PL lines as different soil layers can have different piezometric level In the next section it is described how different PL lines are assigned to different layers It is possible to add insert edit and delete PL lines see Figure 4 48 10 000 21 500 22 500 21 500 54 400 24 000 30 000 24 000 Add Delete Cancel Help Figure 4 48 PL lines window In the lower left part of the window it is possible to use the buttons to add insert and delete PL lines The selection box on the left can be used to navigate between PL lines that have already been defined Use the table to add edit the points identifying the PL lines It is only possible to select points that are not attached to layer boundaries section 4 3 12 Note It is
150. create two new PL lines six new points are first added to the existing points 24 Click Points in the Geometry menu to open the Points window 25 w Click six times the Add row button to add points number lt 25 gt till lt 30 gt which will be used to create PL lines 2 and 3 see section 13 5 2 26 Modify the coordinates of those points number as given in Figure 13 7 27 Click OK Deltares 185 of 264 D GEO STABILITY User Manual Figure 13 7 Points window 13 5 2 PL lines To create two new PL lines follow these steps 28 Click PL lines in the Geometry menu to open the PL Lines window 29 30 31 32 33 Paint ome pem de ii 28 0 000 3 000 2 28 34 750 3 000 gt Fla a 33250 2750 49500 0 250 75 000 0250 Add Insert Delete E Cancel Help Figure 13 8 PL Lines window Click the Add button to add PL line number lt 2 gt Enter points number 25 26 27 23 and 24 inthe Point number column at the right of the PL lines window Click again the Add button to add PL line number 3 Enter points number 28 29 30 23 and 24 in the Point number column at the right of the PL ines window Figure 13 8 Click OK This will result in a new geometry in the View Input window as shown in Fig 186 of 264 Deltares 13 5 3 13 6 Tutorial 6 Reliability Analysis ure 13 9 D View Input o Ims Geometry Input Edt
151. cular to the cross section plane Driving water moment The water moment is the contribution two water moments Mo water Mwater Top a Mwater side 16 3 where IM Water Top is caused by the water forces due to free water on surface acting on the top of the slice see Equation 16 4 M ater Side iS caused by the water forces due to free water on surface acting on the side of the slice see Equation 16 5 and Equation 16 6 Water forces due to free water on surface acting on the top of the slice The water forces acting on and within the soil slice When there is free water on the surface of the geometry and within the boundaries of the slip circle it can have a positive or negative effect on the safety factor The driving water moment Mater for a slice is calculated as follows TL M water Top y Xi ve ENS Cure X WW AT Z cente m Z itap X Whi 16 4 i l where Wi is the vertical component of the water force on top of slice in kN Wi Max 10 Z fliatc Vinee X Yw X b Wa is the horizontal component of the water force on top of slice 2 in kN Whi Max 0 BN sic Zoos X yy X b x tan D Refer to section 1 8 for the definition of the other symbols Deltares 205 of 264 D GEO STABILITY User Manual Water forces due to free water on surface acting on the side of the slice With the introduction of vertical layer boundaries it became possible to have a surface with a vertical component If this vert
152. d then choose Model to display an input window with the following data Calculation methods Model Model Default shear strength f Bishop i phi Spencer Stress tables Fellenius Cu calculated Upitan Cu measured Uplift Spencer Cu gradient Bishop probabilistic random field Pseudo values Horizontal balance Reinforcements Reliability analysis We Geotextiles Enable Soil Resistance zone plot Enable Cancel Help Figure 4 1 Model window Model _ Choose one of the following methods Bishop Usual choice for slope stability analysis Automatically finds a circular slip plane with minimum safety Equilibrium of moments and vertical forces is ensured For background information see section 16 2 Spencer For special slip plane analysis User defined coordinates now fix the slip plane Equilibrium is ensured for moments vertical forces and horizontal forces For background information see section 16 4 Fellenius Obsolete Automatically finds a circular slip plane with minimum safety Only equilibrium of moments is ensured For background information see section 16 2 Uplift Van Usual choice for uplift stability analysis Finds automatically a slip plane with minimum safety The plane consists of a horizontal part bounded by two circles Equilibrium is ensured for moments and vertical forces For background information see section 16 3 Uplift Spencer
153. dd all the available materials in the 44 selected soil group Click the Unselect highlighted material button to delete the selected material gt from the selected soil group Click the Unselect all material button to delete the selected material from the gt selected soil group A soil material can be part of only one soil group Therefore when selected in a group the soil material disappears from the Ungrouped list 4 2 3 4 Materials Reliability Analysis If the Reliability analysis in the Model window is enabled section 4 1 1 D GEO STABILITY uses stochastic values for its calculations On the menu bar click Materials in the Soil menu see Figure 4 31 In this window it is possible to enter material parameters and their statistical descriptions By default the Standard option is selected and allows inputting standard stochastic parame ters 48 of 264 Deltares Materials Maternal name Clay clean moderate Sand sl sil moderate Input Total unit weight KN rrr 19 00 KN rrr 119 00 D efault E phi D efault Mean W Use probabilistic defaults Above phreatic level Below phreatic level Shear strength model f Standard Shear strength input Advanced Shear strength parameters Mean KN Am 25 00 12 92 25 Log normal dea 1 50 i 2 30 2 63 Log normal Cohesion c Friction angle phi Pl pare pressure parameters 10 50 Log normal Add Insert De
154. derived from Triaxial Extension TE tests Active undrained The high value of the undrained shear strength at the active side strength Cu high TC of the slip plane derived from Triaxial Compression TC tests Top The apparent undrained strength C at the top of the layer Bottom The apparent undrained strength C at the bottom of the layer Design value factors The partial factor Joia used by D GEO STABILITY to reduce the Partial unfavorable characteristic value of the undrained shear strength to a safe lower limit section 20 3 6 Deltares 53 of 264 D GEO STABILITY User Manual Design value factors The value of the standard normal parameter Ucharac used by Std dev D GEO STABILITY to calculate the unfavorable characteristic value of the undrained shear strength section 20 3 4 section 20 3 5 Stochastic Gradient undrained cohesion Cu Shear strength model Cu gradient Shear strength input Default Mean M Use probabilistic defaults Horizontal undrained strength Cu DSS Mean Top kN me 16 00 3 37 1 50 og norma Gradient kN m m 0 50 0 28 fo 13 Log normal y Figure 4 40 Cu gradient Standard stochastic input Horizontal undrained Undrained shear strength for a horizontal slip plane derived from strength Cu DSS Direct Simple Shear DSS tests section 19 2 Top The apparent undrained strength s at the top of the layer Gradient The apparent gradient in undrained strength s over the de
155. dom variables is a function of the distance between these points The selected auto correlation function which expresses the correlation among any two points as a function of the distance lags is of a modified Gaussian type 62 2 82 p 0x dy Oz l a a x exp 2 x exp 21 3 with ESI X21 Oy Yi Yo and z1 Zo where D and D are the so called correlation lengths which are related to the scales of fluctuation as introduced by Van Marcke Van Marcke 1983 Typical values of D range between 25 m and 100 m and values of D may range between 0 1 m and 3 m The parameter a is a variance parameter which equals the ratio of local variance i e the variance of fluctuations relative to the mean value along a vertical line and the total variance which is the variance relative to the mean value taken over the whole deposit space 2 O ertical v os 21 A O total For 1 the auto correlation function takes on the classical Gaussian form which is often suggested in literature It was found however that such type may be inconsistent with actual measurements Figure 21 3 shows typical fluctuation behavior of cone resistances in a soft clay layer It appears that averages over depth of the CPT record show considerable differences from one test location to another which cannot be explained when a classical Gaussian function type is assumed The a parameter enables consistent modeling of the pr
156. e a is the angle between the geotextile and the tangent line along the circle where the geotextile intersects the slip circle in degree The contribution of the geotextile depends on the vertical distance between the slip circle center and the geotextile Therefore for acquiring a larger safety factor it is required that this distance is relatively large Only geotextiles that intersect a slip circle contribute to the resisting moment Resisting moment from nails Soil nailing is a technique to reinforce and strengthen the existing ground by installing closely spaced steel bars called nails The bars are usually installed into a pre drilled hole and then grouted into place or drilled and grouted simultaneously They are usually installed at a slight downward inclination A rigid or flexible facing often pneumatically applied concrete otherwise known as shotcrete or isolated soil nail heads may be used at the surface Nails are taken into account in the calculation by considering the forces generated at the intersection with the slip circle Figure 16 5 the lateral force Fy parallel to the nail the shear force Fp perpendicular to the nail Ground Y Figure 16 5 Resisting contribution by nails The design method used for the calculation of both forces Fy and Fp is based on the Clouterre recommendations Clo July 1993 considering four failure criteria Deltares 209 of 264 D GEO STABILITY User Manual section 1
157. e Accuracy Input Soil layers may be identified by their material name their index in the list of materials or their index in the list of layers in the soil profile Mark this check box to display and use a grid Mark this check box to ensure that objects align to the grid automatically when they are moved or positioned Alter this value to modify the default grid distance Mouse selection accuracy define a large value for a large selection area Project Properties Stresses Results The Stresses Results tab allows selecting the way the Stresses and Stresses in Geometry results are presented in the Results windows see section 6 2 and section 6 3 Info bar Legend Layer Colors Rulers Project Properties Identification View Input Stresses Results Fin Grid Results Safety Results General Display jw Rulers W Origin Points v Legend Same scale for s andy axis Large cursor W Loads le Laver Colors W Forbidden lines Labels Layers E As layer numbers lw Loads As material numbers iw Forbidden lines f As maternal names lw Layers Save as default Cancel Help Figure 4 8 Project Properties window Stresses Results tab Mark this check box to display the title panel with the information bar at the bottom of the Stresses Result window Mark this check box to display the legend with soil types Mark this check box to display each soil layer using a different color It is recommended that this opti
158. e added at the end of the rubber band icon instead of the position clicked As with poly lines it is also possible to end a PL line by double clicking the left hand mouse button In this case the automatically added end line will always end at the right limit To stop adding PL lines select one of the other tool buttons or click the right hand mouse button or press the Escape key Measure the distance between two points Click this button then click the first point on the View Input window and place the cross on the second point The distance between the two points can be read at the bottom of the View Input window To turn this option off click the escape key Zoom in Click this button to enlarge the drawing then click the part of the drawing which is to be at the center of the new image Repeat if necessary Zoom out Click this button then click on the drawing to reduce the drawing size Repeat if necessary Zoom rectangle Click this button then click and drag a rectangle over the area to be enlarged The selected area will be enlarged to fit the window Repeat if necessary Add geotextile In this mode it is possible to use the left mouse button to graphically define the starting and end point of a geotextile section The stability of a slope will increase If a slip plane crosses a geotextile Add nail In this mode it is possible to use the left mouse button to graphically define the starting and end point of a nail T
159. e standard deviation o p and the auto correlation function rp in the out of plane direction Out of plane analysis The Bishop probabilistic model calculates for each of the failure circles the probability of oc currence of a potential failure zone based on the results of the first step Calculation is based on the concept of first exceeding events in the theory of stationary stochastic processes as suming the occurrence of an event F Z lt 1 somewhere in a stretch of length L as a rare Poisson event The last step is explained below The probability of occurrence of a potential failure zone may by approximation be calculated as P F 2 lt Freire Z 0 L 75 f PND With I where 7 0 denotes the second derivative at zero lag of the modified auto correlation func tion of the safety factor see Equation 21 5 The width of a potential failure zone is exponentially distributed Its expected mean value equals Br Eu A 21 7 pu Nz 21 7 The above approximation is valid for small probabilities i e for 6r values greater than say 1 5 Finally the Bishop probabilistic model calculates the probability of real occurrence of a 3D failure mode with finite width equal to ju as 61 P F l P F 1 0 L 21 8 ie GE PEO Lee 0 0 21 8 with AFt AM d Bi 21 9 2 2 O Me Ow F pj M where F denotes the stability factor of the failure mode including the edge c
160. e Add mode allows the addition of elements using one of the Add but tons By selecting one of these buttons one switches to the Add mode As long as this mode is active the user can add the type of element which is selected The Zoom mode allows the user to view the input geometry in different sizes By selecting one of the Zoom buttons or the Pan button one activates the Zoom mode While in this mode the user can repeat the zoom or pan actions without re selecting the buttons It is possible to change modes in the following ways When in Add or Zoom mode it is possible to return to the Select mode by clicking the right hand mouse button or by pressing the Escape key or by clicking the Select mode button To activate the Add mode select one of the Add buttons To activate the Zoom mode select one of the Zoom buttons or the Pan button Deltares 105 of 264 D GEO STABILITY User Manual Note The current mode is displayed on the info bar at the bottom of the View Input window 7 3 2 Buttons Select and Edit mode In this mode the left hand mouse button can be used to graphically select a previ ously defined grid load geotextile or forbidden line Items can then be deleted or modified by dragging or resizing or by clicking the right hand mouse button and choosing an option from the menu displayed Pressing the Escape key will return the user to this Select and Edit mode Pan Click this button to change the visible part of t
161. e Areas for Safety window section 4 4 4 Note A slip surface passing through zone 1 but with an entrance point in zone 2 is ac cording to the zone plot method defined as a slip surface in zone 2 only if the modified slip surface deformed situation after rotation satisfies the required safety factor for zone 1 For background information on the determination of the modified slip surface refer to section 22 2 9 Safety Factor per Zone 8 10 Safety factor model factor T T T T T T T T T T T T T T T T 30 000 35 000 40 000 45 000 Entry point active circle m Zone 1a minimum 1 104 After rotation zone 2 previously zone 1 Zone 3a minimum 1 104 Zone 2a minimum 1 Zone 2b minimum 1 162 o Zone 3b minimum 1 162 Figure 6 10 Safety Factor per Zone window Stresses per Zone In case of a Zone plot calculation section 4 1 1 click the Stresses per Zone option in the Results menu to open the Critical Circle window Figure 6 11 Click the Previous zone and Next zone icons to view various calculated results for each zone o Graphical representations of the critical circle divided into a certain number of slices By double clicking on a certain slice a special window is displayed containing detailed information on that slice Key information like the radius and center coordinates of the critical circle and the safety factor are printed in the status panel at the bottom o
162. e alternative safety factor is equal to 1 81 1 05 1 72 The measurements of the left slip circle are given as this is the more deciding factor in the determination of the safety factor The measurements of the right slip circle are found in the report Note lt is possible to compare results obtained by the Uplift Van method to those of other methods E g the Bishop method in this case gives a result with a slip circle with a large radius and a higher safety factor Deltares 179 of 264 D GEO STABILITY User Manual M nass tttttt E Sand 444444 444444 444444 444444 444444 444444 444444 44444 444444 4444 44444 44444 A Xm 30 50 m Radius 23 00 m Ym 15 00 m Safety 1 81 1 72 X 47 727 v 24 200 Edit Figure 12 10 Slip Plane window 12 7 2 FMin Grid The FMin Grid window also shows the grid of the left slip circle 37 Click FMin Grid in the Results menu to open the FMin Grid window Figure 12 11 The minimum safety factor of 1 805 is indicated in red D So 11819 1811 812 1 821 YY 806 E 807 ES 807 d En xS 807 1 813 ec 1 807 Yip E xm 30 50 m Radius 23 00 m Max isoline 1 88 No of isolines 11 Ym 15 00 m Safety 1 81 1 72 Min isoline 1 81 x 32 477 Y 19 324 Edit Figure 12 11 FMin Grid window 12 8 Conclusion In this tutorial the soil conditions and piezometric levels are such that it is probabl
163. e bottom of slice 7 in kN m see Equation 18 6 Di is the internal friction angle of the soil at the bottom of slice 2 in degree Qi is the angle at bottom of slice in degree P is the safety factor see Equation 16 28 in section 16 2 3 Shear stress Fellenius When using the shear strength option c phi or Stress Table together with the Fellenius calcu lation method D GEO STABILITY will use the following formula for the shear stress 7 acting at the bottom of each slice T Ci Oya X cos oj uj X tan Qj 16 10 where C is the cohesion at the bottom of slice 7 in KN m Oy is the total vertical stress at the bottom of slice 2 in KN m see Equation 18 7 Uj is the total pore pressure at the bottom of slice 7 in KN m see Equation 18 5 O is the internal friction angle of the soil in degree ay is the angle at bottom of slice in degree Resisting moment from geotextiles Geotextiles can be used to reinforce and improve the stability of slopes The geotextile intro duces a force that can act at the boundary of a slip circle see Figure 16 4 Figure 16 4 Resisting contribution by geotextiles When calculating the safety factor for the Bishop method an extra resisting moment due to 208 of 264 Deltares 16 2 2 3 Method of slices the geotextile Mp geotextile is introduced where Tf isthe tensile strength in kN m as defined in the Geotextiles window section 4 5 1 k isthe radius of the slip circl
164. e circle The following can be reasons for rejecting a circle circle cuts the surface less than two times circle cuts the surface an uneven number of times circle cuts a forbidden line circle center point is too low circle center is located within the geometry too many slices driving moment too small limit 2 0 001 resisting moment too small limit 2 0 001 more than maximum number of iterations required 000000000 The following are possible output notes about a slip circle Deltares 91 of 264 D GEO STABILITY User Manual circle cuts surface gt 2 times gt piece X till taken to indicate which part of the slip circle is used if the circle intersects the surface more than two times occurrence of negative effective stress evaluated earlier in former grid position This table can become very long depending on the number of circles for each grid and the number of times the grid is moved in search of a minimum safety factor Report Information about critical slip plane If a slip plane was found with a minimum safety factor the following information is displayed about that slip plane ixl CEE dod ee ele didis dodo dedos dodo ee alps et Seat dodo E E E E dodo dedo ab kp nat ee dodo dodo AAA AAA The input has been tested and is correct 4444484640 08088 fae e dede aie ele air dede de dede de dede de de dede de dec dede de dede de aie ate ake ate de de dede de de de de de de de de d
165. e to expect a non circular slip plane That s why the Uplift Van model is used as it evaluates the safety factor of a soil structure finding a non circular slip plane 180 of 264 Deltares 13 Tutorial 6 Reliability Analysis 13 1 In this tutorial an example is given of a probabilistic calculation D GEO STABILITY has the possibility of describing soil parameters stochastically In addition it is possible to describe different water levels and provide their frequency of exceeding After D GEO STABILITY per forms a probabilistic calculation the output will consist of a safety factor and the probability of failure at each given water level Also the parameters which influence the outcome most are named and their influence represented by a percentage The objective of this tutorial is To learn how to describe input into D GEO STABILITY stochastically For this example the following D GEO STABILITY modules are needed D GEO STABILITY Standard module Bishop and Fellenius Uplift Van model Reliability model This tutorial is presented in the file Tutorial 6 sti Introduction to the case In order to gain insight into the probability of failure of a soil structure and assess the influence of model input D GEO STABILITY performs a probabilistic calculation To this end input has to be described stochastically This input includes material and model properties as well as an option to describe different occurring water levels
166. e tutorial section provide a convenient starting point for familiarization with the program 3 1 File menu Besides the familiar Windows options for opening and saving files the File menu contains a number of options specific to D GEO STABILITY New Select this option to display the New File window Figure 3 1 Three choices are avail able to create a new geometry 0 Select New geometry to display the View Input window showing only the geometry limits with their defaults values of the geometry H Select New geometry wizard to create a new geometry faster and easier using the wizard option involving a step by step process for creating a geometry see section 4 3 2 H Select mport geometry to use an existing geometry New File EE Geometry C New geometry wizard C Import geometry Figure 3 1 New File window o Copy Active Window to Clipboard Use this option to copy the contents of the active window to the Windows clipboard so that they can be pasted into another application The contents will be pasted in either text format or Windows Meta File format Export Active Window Use this option to export the contents of the active window as a Windows Meta File wmf a Drawing Exchange File dxf or a text file txt o Page Setup This option allows definition of the way D GEO STABILITY plots and reports are to be printed The printer paper size orientation and margins can be defined as well as whether and
167. e2 Dike reinforced with berm 000000 0 Thea Poo Date 1 13 2011 iw Use current date Drawn by gt Project ID PO Annex ID MEE Save as default Cancel Help Figure 4 6 Project Properties window Identification tab Titles Use Title 1 to give the project a unique easily recognizable name Title 2 and Title 3 can be added to indicate specific characteristics of the calculation The three titles will be included on printed output Date The date entered here will be used on printouts and graphic plots for this project Either mark the Use current date check box on each printout or enter a specific date Drawn by Enter the name of the user performing the calculation or generating the printout Deltares 33 of 264 D GEO STABILITY User Manual Project ID Annex ID Enter a project identification number opecify the annex number of the printout Enable the check box Save as default to use these settings every time D GEO STABILITY is started or a new project is created Project Properties View Input Use the View Input tab to specify the availability of components in two tabs of the View Input window section 2 2 3 Praject Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Display jw Rulers W Origin Iw Points Iw Loads Iw Forbidden lines e Legend Same scale far and y axis Large cursor le Layer Colors Labels Layers Grid As layer nu
168. ecessary Zoom rectangle Click this button then click and drag a rectangle over the area to be enlarged The selected area will be enlarged to fit the window Repeat if necessary Measure the distance between two points Click this button then click the first point on the View Input window and place the cross on the second point The distance between the two points can be read at the bottom of the View Input window To turn this option off click the escape key Aad geotextile In this mode it is possible to use the left mouse button to graphically define the starting and end point of a geotextile section The stability of a slope will increase if a slip plane crosses a geotextile Add nail In this mode it is possible to use the left mouse button to graphically define the starting and end point of a nail The resistance of the soil will increase Add fixed point Click this button to graphically define the position of a point that will be part of the critical slip circle 17 of 264 2 2 4 D GEO STABILITY User Manual X Aad calculation grid Click this button to graphically define the initial position of the trial grid with slip circle center points and the corresponding positions of the trial horizontal tangent lines of the slip circle Undo zoom Click this button to undo the zoom If necessary click several times to retrace each consecutive zoom in step that was made Zoom limits Click this button to display the complete
169. ect the Bishop model using a circular slip plane From the Soil menu select Materials and set the Default shear strength to C phi Set the cohesion and friction angle for each layer see Table 8 1 Unmark the Geotextiles and Nails check boxes as no geotextile or nail is used in this tutorial Click OK to confirm See section 4 1 1 Model for a detailed description of this window Project Properties To give the project a meaningful description follow the steps described below 27 On the menu bar click Project and then choose Properties to open the Project Properties window Figure 8 10 28 Fill in lt Tutorial 1 for D GEO STABILITY gt and lt Dike reinforced with berm gt for Title 1 and Title 2 respectively in the dentification tab The settings of the others tabs of the Project Properties window are set to their default values 126 of 264 Deltares Tutorial 1 Dike reinforced with berm Project Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Tie 1 Tutorial for D Geo ab Tile2 Dike reinforced with bem 0 Sn Date 1A172011 Drawn by o Project ID PO Annex ID MEE Save as default Cancel Help Figure 8 10 Project Properties window Identification tab In the other tabs of the Project Properties window some defaults values are modified in order to make the graphical geometry input section 8 9 1 and the view results section
170. ede de ake ate de de de de de de de de de dede de de de de ate ate de de de de dede de de de dede RESULTS OF THE SLOPE STABILITY ANALYSIS The center point of the critical circle lies on the edge of the grid New grid with X minimum 3 27 m X maximum 2 83 m Y minimum 1 92 m Y Y maximum 92 m Information on the critical circle lt Fmin 1 584 Calculation method used z Bishop C phi X co ordinate center point 5 45 m co ordinate center point z 5 25 m Radius of critical circle 37 m The center point of the critical circle is enclosed Total driving moment x L 60 kNm m Driving moment free water 1 kNm m Driving moment external loada 1 00 kNm m Iterated resisting moment a kNm m Non iterated resisting moment 05 kNm m END OF D Geo Stability OUTPUT Figure 6 1 Report window for Bishop method The calculated minimum safety factor and the position of the circle are displayed If the center point is enclosed this is noted If not the side of the grid where the minimum safety factor was found is displayed An iterative process determines the resisting moment in the Bishop method The non iterated resisting moment is the resisting moment in the first iteration with F 1 0 With the changing of Fin each iteration the resisting moment also changes and the moment in the last iteration is given by the Iterated resisting moment This moment should be approximately equal to the abso
171. ee the Materials option in the Soil menu section 4 2 3 1 is displayed On the right a list of all defined layers together with their assigned materials if available is displayed Note that the layers are listed from top to bottom as displayed in the View Inout Geometry window EB To assign a material to a layer first select that layer on the right of the window Then select the required material on the left of the window Finally click the Assign button PL lines per Layer Use this option to define the top and bottom PL lines for the defined layers The PL lines represent the pore pressure in a soil layer For each soil layer except the deepest layer two PL line numbers can be entered one that corresponds to the top of the soil layer and one that corresponds to the bottom Therefore different PL lines can be defined for the top and bottom of each soil layer see section 4 3 13 To do this select the appropriate PL line at top PL line at bottom field and enter the appro priate number see Figure 4 52 Note D GEO STABILITY has reserved two numbers for special cases Also use the special values 0 and 99 D GEO STABILITY s Darcy model expects only input for layers with fixed head as it will calculate by itself the distribution inside clusters of compressible layers Deltares 63 of 264 D GEO STABILITY User Manual PL lines per Layer Layer PL line PL line Number at top at bottom Fi 1 B D EG 1
172. eference level of the soil surface Figure 19 3 in kN m This reference level defines the initial surface before embankment addition O is the actual effective vertical stress after embankment addition in kN mf POP _ is the pre overburden pressure in kN m POP OCR 1 x o OCR _ is the over consolidation ratio Stress induced anisotropy The shear strength ratio in over consolidated soil is larger at the active side of the slip plane and smaller at the passive side An average value at the horizontal part of the slip plane follows from a direct simple shear test DSS A small passive value follows from a triaxial test in extension TE A high active value follows from a triaxial test in compression TC D GEO STABILITY can model this stress induced anisotropy by assuming a shear strength ratio that varies with a sinus function along the orientation of the slip plane Figure 19 3 The function is defined by the input of the average value the minimum value at the passive side and the maximum value at the active side Deltares 235 of 264 D GEO STABILITY User Manual Heference level active CulPc L 7 1c DSS 90 0 9 passive 90 angle Figure 19 3 Reference level and stress induced anisotropy 19 4 Pseudo values When using the shear strength option Pseudo values section 4 2 3 1 D GEO STABILITY will calculate the shear stress along the slip plane assuming a stochastic normal shear strength
173. efined by PL lines section 20 4 3 Stochastic Cohesion and friction angle c phi Select the Advanced button to access both regular and special shear strength parameters Cohesion Friction Angle Shear strength model Default C phi Standard Shear strength input Default Mean Use probabilistic defaults C Advanced Shear strength parameters Mean Cohesion c KN 4m 25 00 12 92 8 25 Friction angle phi deg 17 50 12 30 2 63 Figure 4 32 C phi Standard stochastic input The cohesion c The internal friction angle Shear strength model Default E phi Y Standard Shear strength input Default Mean kal W Use probabilistic defaults y Advanced Shear Strength Shear Strength Advanced Fore Pressure Correlation co efficient cohesion and tan phi Design value factors Partial Design value factors Std dev Correlation coefficient cohesion and tan phi 10 00 Cohesion design value factors Phi design value factors Figure 4 33 C phi Advanced stochastic input The correlation coefficient defines the dependency between variations of cohesion and tan phi A value of 1 means that both parameters will vary equally with respect to the mean value A zero value means that the parameters can vary independently A zero value is a safe assump tion The partial factor JF partial used by D GEO STABILITY to reduce the unfavor able characteristic value of cohesion and
174. el 2 0 P h gt Eign exp exp 5 design 22 20 23 Parameter 5 is the decimate height the increase of the external water level that reduces the exceeding probability with a factor 10 D GEO STABILITY determines the parameter Ugumbe from the input values of B the design level Adesign and the allowed exceeding frequency at the design level Stochastic model factor It is possible to model all remaining uncertainty on the 2D calculation model the loads and the geometry via the global model factor This factor represents the required safety factor Frequired by a mean value and a standard deviation The default D GEO STABILITY values are safe values obtained from Dutch research on water retaining structures Experience with these safe values indicates that the model factor will generally dominate the 246 of 264 Deltares Reliability analysis probability of failure To eliminate this influence for example for the purpose of an automated sensitivity analysis then it is also possible to set the assumed distribution for the model factor to none and set the mean value of Frequirea equal to the value normally used for a design value analysis Deltares 247 of 264 D GEO STABILITY User Manual 248 of 264 Deltares 21 21 2 21 3 Bishop probabilistic random field This chapter describes the specific usage and background of the Bishop probabilistic random field module formerly known as MProStab This module h
175. el and the Uplift Van model The Reliability analysis module applies the probabilistic FORM procedure only on the slip surface position that has been determined from a preceding mean value analysis 244 of 264 Deltares 20 4 3 20 4 4 Reliability analysis It is possible to manually check if this position results in the lowest value of the reliability index by performing separate calculations for fixed adjacent positions The FORM procedure can not be used to determine the probability of failure that is caused by significant contributions from multiple failure modes o The FORM procedure is not guaranteed to give a minimum value for the probability of failure Stochastic hydraulic pore pressure Hydraulic pressure is caused by gravity hydrostatic part and by hydraulic boundary condi tions D GEO STABILITY derives the hydraulic pressure from the user defined PL lines at the top and bottom of each layer using a linear interpolation D GEO STABILITY assumes that the standard deviation of the phreatic line equals the user defined standard deviation of the hydraulic pressure of the soil type to which the phreatic line is attached The standard deviation of the hydrostatic pressure component in all layers is equal to the standard deviation of the phreatic surface User defined standard deviations of hydrostatic pore pressures in layers below the phreatic surface should not be less than the standard deviation of the hydrostatic pre
176. eometry of Figure 12 1 needs to be inputted in D GEO STABILITY This is done using the Geometry Wizard as for Tutorial 1 section 8 2 When the Wizard is completed modifications to change and complete the geometry will be made using the Geometry menu To create a new geometry using the Wizard follow the steps described below 1 Click File and choose New on the D GEO STABILITY menu bar 2 Select New geometry wizard and click OK 3 Enter the basic geometrical properties the basic geometric situation with the geometric values and the soil type for each layer as given in Figure 12 2 New Wizard New Wizard Define measurements basic layout Select top layer shape by clicking on the desired pictur cum di A A A Ground Level Phreatic Level Limit left m 000 8 Limit right m foo Number of layers max 10 HH I Ground level m po Phreatic level m 0 75 New Wizard New Wizard Set material types Set all layers to material type Nr ial Layer Nr Material Type Soft Clay 1 Sand Y 2 Peat v E Apply 3 Soft Clay y 4 Loose Sand y Show properties of material type Soft Clay v h m 5 00 L1 m 12 50 L2 m 6 00 L3 m 12 50 Properties Figure 12 2 New Wizard windows 4 Click Finish in the last New Wizard window which gives an overview of the inputted geom etry A View Input window appears Figure 12 3 with the D GEO STABILITY geometry that has been created so
177. er Manual xviii Deltares 1 1 1 2 General Information Foreword More than a century ago notorious slope failures have marked the start of geo engineering A major slope failure in Berlin in 1879 massive slope failures during construction of the Panama Canal in 1909 a quay collapse in Gothenburg Sweden in 1916 and a dramatic railway em bankment collapse in The Netherlands in 1918 These events triggered authorities and en gineers to better understand what really happened In a swift response scientific committees established by the authorities stated that water pressure is likely a major culprit In 1925 Prof Terzaghi astonished these committees with the first basic book on the principles of soil mechanics and since then the profession of geo engineering got real impetus Though in Sweden Fellenius designed an elegant and practical circular method to evaluate slope stability around 1916 already in 1846 Alexander Collin had shown the relation of water and strength of clay and proved that a slip surface is actually a cycloid Collin s work was forgotten It was rediscovered a century later and applied in Lorimer s method Since then Taylor Bishop Morgenstern Price Janbu and Spencer have developed practical methods and de Josselin de Jong improved the fundamentals by the double sliding mechanism The existence of various methods reveals that there is no absolutely correct method and special care and experience are required when appl
178. er The number of grid points in vertical direction Tangent Line 66 of 264 Deltares Input Y top The initial vertical coordinate of the highest tangent line of a trial slip circle Y bottom The initial vertical coordinate of the lowest tangent line of a trial slip circle Number The number of tangent lines in vertical direction Fixed Point Use Fixed Enforce a slip circle through a particular point Point X fixed The horizontal coordinate of the fixed point Y fixed The horizontal coordinate of the fixed point This coordinate must be above the Y bottom coordinate of the tangent lines 4 4 1 2 Slip Plane Definition Uplift Van Uplift Spencer The following applies when the Uplift Van or Uplift Spencer method is selected section 4 1 1 The plane for uplift stability consists of a horizontal part bounded by a circle at the ac tive side and a circle Uplift Van or a straight plane Uplift Spencer at the passive side D GEO STABILITY determines the critical plane in iterative way The trials that D GEO STABILITY performs are based on two grids of center points and one horizontal tangent line The grids can move towards the direction with the lowest safety factor during the calculation process The position of the tangent line is fixed and should be located at the interface between imper meable weak layers and underlying sand layer In the input window the initial location of the grids and the fixed location of the horizontal
179. ering channel on the right must be selected to be in accordance with Figure 8 1 Deltares 121 of 264 D GEO STABILITY User Manual New Wizard Select top layer shape by clicking on the desired picture JA Ah A A Ah lh A A lt Previous Nent gt Cancel Help Figure 8 4 New Wizard window Basic geometric situation 9 Select the option with a dike with a dewatering channel on the right also indicated in Figure 8 4 10 Click Next Note Within the Wizard it is always possible to navigate between the wizard windows using the Previous and Next buttons 8 2 3 Wizard Shape definition In the next window Figure 8 5 the geometric values of the dike body and the dewatering channel can be set 122 of 264 Deltares Tutorial 1 Dike reinforced with berm Define measurements Far top layer shape hi m 5 00 17 50 h2 m 200 EOD foo Previous Cancel Help Figure 8 5 New Wizard window Top layer measurements In Figure 8 1 the measurements of the dike and the dewatering channel have been depicted 11 Fill in the values in Figure 8 5 to provide the measurements for the top layers 12 Click Next 8 2 4 Wizard Material types The next window Figure 8 6 allows choosing a soil type for each layer from the drop down menus beside the layer numbers Later it is possible to modify properties including strength properties of the soil types Deltares 123 of 264
180. ers MStab version 6 0 was released in 1995 This version included a major alteration to the geometry file and a more flexible way of adding and deleting points and layer boundaries Furthermore each soil layer now had to be assigned a soil type while soil properties were in turn assigned to a soil type As a result these properties were linked to the soil layers through the soil type Lastly traffic loads became temporarily distributed loads with a degree of consolidation for each layer MStab version 7 0 was released in 1998 the first Windows version of MStab MStab version 8 0 1999 contains further improvements including the option of non circular slip planes MStab version 9 0 2001 includes an enhanced module for geometrical modeling and im proved versions of the user manual and on line Help have been released MStab version 9 7 2002 includes separately licensed modules for the general Spencer method and for the new Uplift Van and Uplift Spencer methods The new methods deter mine automatically a slip plane in cases with excessive interface water pressures MStab version 9 8 2004 contains the following new features Reliability Analysis module Bishop Probabilistic Random Field module calculated undrained cohesion combination of material models MStab version 9 10 August 2007 contains the following new features Tree on slope Zone plot Pseudo values shear strength model and Horizontal balance check D
181. erties Identification View Input Stresses Results FMin Grid Results Safety Results General Display v Info bar iw Rulers v Origin Paints e Legend Same scale far and y axis Large cursor Iw Loads le Laver Colors W Forbidden lines Labels Layers As layer numbers jw Loads f Az material numbers 4 Forbidden lines fe As material names jw Layers Save as default Cancel Help Figure 8 12 Project Properties window Stresses Results tab 35 Select the FMin Grid Results tab Figure 8 13 to change the settings of the FMin Grid window section 8 8 4 36 Mark the Use values from results check box to display the iso lines with a range automati cally calculated by D GEO STABILITY 37 Mark the Points labels check box to display the safety factor of each point of the FMin grid Project Properties Identification View Input Stresses Resulte FMin Grid Results Safety Results General Display W Info bar jw Rulers Large cursor Iw Point labels Escocoopacoooongens Same scale far and y axis W zalines Lines Mumber af lines Iw Use values from results Iw Display line numbers Save as default Cancel Help Figure 8 13 Project Properties window FMin Grid Results tab 38 Select the Safety Hesults tab Figure 8 14 to change the settings of the Safety Overview window section 8 8 5 39 Select the As material names in the Layers sub window to display the material name of the di
182. es4 D GeoStability Use MGeobase database MGeobaze database El Cancel Help Figure 3 4 Program Options window Locations tab Working D GEO STABILITY will start up with a working directory for selection and directory saving of files Either choose to use the last used directory or specify a fixed path MGeobase Here it is possible to assign a database location This database gdb database or mdb can be accessed with several options in D GEO STABILITY to retrieve D GEO STABILITY specific data from this file location Program options Language Program Options View General Locations Language Modules Interface language English T Output language English E Cancel Help Figure 3 5 Program Options window Language tab Select the language to be used in the D GEO STABILITY windows and on printouts Interface Currently the only available interface language is English language Output Two output languages are supported English and Dutch The selected language output language will be used in all exported reports and graphs 26 of 264 Deltares 3 3 3 3 1 General Program options Modules Program Options View General Locations Language Modules License FlesLm We D Geo Stability Standard module Bishop and Fellenius le Spencer module e Uplift module le HReliabilitu Analyses module Iw Probabilistic Random Field module jw Show at start of progr
183. esence of overall weak and strong locations within a layer For fluctuations of cone resistance in clayey layers o values ranging between 0 5 and 1 0 have been found Figure 21 3 Typical pattern of spatial fluctuations of cone resistances in a soft cohesive layer Parameters of the probability distributions i e expected mean values and standard devia tions must be estimated on the basis of series of laboratory or in situ test results Usually the Deltares 253 of 264 21 5 2 21 5 3 D GEO STABILITY User Manual number of available test results will be limited which implies that estimates are statistically biased Bias of the estimation of the expected mean value is a source of uncertainty which is correlated throughout the soil layer and it must be taken into account in the probabilistic analysis This has been done in the computation model by adjusting the field variance with a factor n 1 n and modifying the auto correlation function into 1 n r Ox On 6 pa x On 6 ES El 21 5 where n is the number of test samples If both c and tan y are estimated from test results of the same experiment e g triaxial test the estimates are negatively correlated In the stochastic field model it is assumed that the fluctuation fields of the two parameters are not correlated Correlation among estimates c and tan p from the test result of a sample results in correlated estimates of the expected mean values of these para
184. ess Po Mean Passive low TE 0 22 0 1 2 10 06 Log normal Active high TC 0 22 0 1 5 10 06 Log normal Ratio Cu Pc design value factors 1 15 1 65 POP design value factors 11 10 1 65 Figure 4 37 Cu calculated Advanced stochastic input Uniform ratio Unselect this option to define stress induced anisotropy for over Cu Pc mean design Ratio Cu Pc Passive low TE Ratio Cu Pc Active high TC Design value factors Partial Design value factors Std dev consolidated soil section 19 3 The mean value of the ratio section 20 3 1 The design value of the ratio section 20 3 6 The low value of the undrained shear strength ratio resulting from Triaxial Extension tests The high value of the undrained shear strength ratio resulting from Triaxial Compression tests The partial factor foartia used by D GEO STABILITY to reduce the un favorable characteristic value of the undrained shear strength ratio Cu Pc and pre overburden pressure POP to a safe lower limit sec tion 20 3 6 The value of the standard normal parameter Ucharac used by D GEO STABILITY to calculate the unfavorable characteristic value of the undrained shear strength ratio Cu Pc and pre overburden pres sure POP section 20 3 4 section 20 3 5 Stochastic Measured undrained cohesion Cu 52 of 264 Deltares Input Shear strength model Cu measured f Standard Shear strength input Def
185. ess for creating a geometry Deltares 57 of 264 4 3 2 4 3 3 4 3 4 D GEO STABILITY User Manual New Wizard Use this option to start the wizard which will guide the user step by step through the process of creating a geometry For a detailed description see Tutorial 1 chapter 8 Using this wizard significantly reduces time and effort required to enter data Import This option displays a standard file dialog for selecting an existing geometry stored in a geom etry file Existing input files for D SETTLEMENT formerly Known as MSettle D GEO STABILITY D GEO PIPELINE formerly known as MDrill or MSeep are also supported For a full description of these programs and how to obtain them visit www deltaressystems com When selecting the geometry it is imported into the current project replacing the current geometry The imported geometry is displayed in the View Input Geometry window It is also possible to use this option to analyze the settled geometry at different stages as all other input is retained Click Import in the Geometry menu The Import Geometry From dialog will appear see Figure 4 44 Choose the desired geometry and click Open Import Geometry From 4 Tutorial 1a sti Pa E Mame Date modified Type e q 7 P Tutorial 1a 10 1 2010 10 20 AM STIFile P Tutorial ib 10 1 2010 10 20 AM STI File P Tutorial 2 10 1 2010 10 20 AM STIFile P Tutorial 3 10 1 2010 10 20 AM STI File P Tutorial 4a 10
186. etion of elements 115 7 5 3 Using the right hand mouse button 116 7 5 4 Dragging elements Drag anddrop 118 Tutorial 1 Dike reinforced with berm 119 8 1 Introduction to the case 2l lll lr 119 V D GEO STABILITY User Manual 8 2 Creating a new file using the Geometry Wizard 120 8 2 1 Wizard BasicLayout lll rrr 121 8 2 2 Wizard Shape selection rr 121 8 2 3 Wizard Shapedefinition 122 8 2 4 Wizard Material types 0 000008 2G 123 8 2 5 Wizard Checking a 0 eee ee ee es 124 8 2 6 View Input e ww qom o de ow OX de Bee CRT Oca d 125 Dl FI oo s wee xo Qe amp O3 3eo OX dO a m MAR doc wed 126 8 3 1 Mod l ate do Room ooo bee de bow oe ewe x 3 126 8 3 2 Project Properties uo v book o o 9 Ow X 3 eee dress 126 84 QGeometty MB 130 8 4 1 Points coso ora aso x m eum cs 130 84 2 PL lines 22ME 131 8 4 3 PL lines per layer e 132 8 44 Check Geometry 2 2 2 2 2 133 85 3S S0oill 2 ooo NAM oS 133 86 Definitions 49 A 134 8 7 Calculation cociendo sa vo uuo 99 ooo 135 88 Results lt lt BO O 136 8 8 1 Report 4m 4 136 8 8 2 Stresses in
187. etween ground and bond given by Equa tion 16 16 is the limit shear force when soil fails in bearing below the nail given by Equa tion 16 19 is the limit shear force when nail breaks in bending given by Equation 16 24 is the yield force in tension as inputted in the Nail Type tab of the Nails window Figure 4 69 210 of 264 Deltares Method of slices The total force in the nail is Frat Fe FA 16 14 The extra resisting moment Mp naj due to the nail is Mr nail Mp Mn 16 15 with Mp Frail x cosd x R Mn Fui X sin x tan y x R where Mp MN M is the moment due to the projection of Fra on the tangent line along the circle in kNm is the moment due to soil friction in KNm is the radius of the slip circle in m is the angle between the nail force Fai and the tangent line along the circle where the nail intersects the slip circle in degree Fi Q arctan 2 N is the angle between the nail and the tangent line along the circle where the nail intersects the slip circle in degree 16 2 2 3 1 Tensile resistance at soil nail interaction during pull out Reaching the pull out capacity of soil nails can be assessed by the following criteria FN X ENa Todi T X DEBIL 16 16 where Tm ax D La Lshear Deltares is the ultimate frictional resistance to pull out between ground and bonded length in kN m If Input of ultimate shear stress along nail is selected
188. f the initial slip plane which is 10 Figure 11 17 suggests a shape for the second slip plane red line Deltares 167 of 264 D GEO STABILITY User Manual P View Input oO mesa Geometry Input Materials E Dike sand E Dike sand 2 EJ Stiff clay C Peat E Clayey sand C Pleistoceen sand b TNI o 235 5 20 25 a 157 h 111 cf ALLE LEELELLEI x 103 750 v 31 750 E dit Current object Spencer Slipplane Figure 11 17 View Input window Input tab Suggested second slip plane Tutorial 4b 48 Click Slip Plane in the Definitions menu to view the properties of the slip planes to be created using the two that are now provided Figure 11 18 49 Modify the coordinates first and second columns of the first slip plane to be in accordance with the values of Figure 11 18 50 Modify the coordinates third and fourth columns of the second slip plane just inputted manually to be in accordance with the values of Figure 11 18 The Generate slip planes box is now automatically marked Set the transversal grid points to 27 This will create 1024 slip planes in the space confined by the two defined slip planes The amount of slip planes for which D GEO STABILITY will calculate the safety factor is equal to the number of transversal grid points number of points defining slip plane 51 Click OK P Slip Plane Definition Ok Cancel Help Figure 11 18 Slip Plane Definition
189. far At this point the geometry needs to be saved 5 Click Save as in the File menu 174 of 264 Deltares Tutorial 5 The Uplift Van model 6 Enter Tutorial 5 as file name 7 Click Save E Sand x 82 000 Y 0 000 E dit Current object None Figure 12 3 View Input window Geometry tab 12 3 Model As the Bishop method the Uplift Van method can also be used to calculate the safety factor of many different slip surfaces and ensures vertical force equilibrium and moment equilibrium 8 Click Model in the Project menu 9 Select the Uplift Van model 10 Unmark the Geotextiles and Nails check boxes as no geotextile or nail is used in this tutorial 11 Click OK 12 4 Soil materials In the Soil menu it is possible to modify the properties of the soil layers to be in accordance with Table 12 1 12 Choose Materials from the Soil menu to open the Materials window Deltares 175 of 264 12 5 12 5 1 D GEO STABILITY User Manual 13 14 15 16 17 Materials Parameters Database Material name Clay Total unit weight Peat Above phreatic level kM rr 17 00 Pan Below phreatic level kM rrr 17 00 Shear strength model Default C phi Cohesion c kN re 5 00 Friction angle phi deg 20 00 Add Insert 4 Delete Rename v Cancel Help Figure 12 4 Materials window Select Loose Sand in the material list Click Rename and change Loose Sand into lt Dike sand
190. fferent layers 128 of 264 Deltares Tutorial 1 Dike reinforced with berm 40 Enter values of 1 35 in the Safe gt box and lt 1 15 gt in the Fail box to define respec tively the safe and failure areas as given in the tutorial introduction section 8 1 Praject Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Display vr Info bar jw Rulers vw Origin Paints e Legend Same scale far and y axis Lange cursor Iw Loads jw Laver colors Iw Forbidden lines Labels Layers Safety limits E As layer numbers i Loads C As material numbers Safe gt 135 iw Forbidden lines As material names jw Layers Fail lt 1 15 Save as default Cancel Help Figure 8 14 Project Properties window Safety Results tab 41 Select the General tab Figure 8 15 to check that the results will be displayed in kilo Newton and meters Praject Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Labels fe kilo Newton and meters kM and m Newtons and millimeters M and mm Loads Size 2 00 W Lise default size Figure 8 15 Project Properties window General tab 42 Before closing the Project Properties window mark the Save as default check box to use the settings previously inputted every time D GEO STABILITY is started which mean for the other tutorials 43 Click OK to confirm See section 4
191. friction angle to a safe lower limit section 20 3 6 The value of the standard normal parameter charac used by D GEO STABILITY to calculate the unfavorable characteristic value of co hesion and friction angle section 20 3 4 section 20 3 5 Stochastic Stress table Sigma Tau 50 of 264 Deltares Input Shear strength model Stress tables Standard Shear strength input Default Mean v Use probabilistic defaults Advanced Shear strength parameters Stress table Btw AL Basisveen Y Figure 4 34 Stress table sigma tau Standard stochastic input Stress table Select a previously defined or imported stress table section 4 2 1 sec tion 19 1 section 20 3 3 Distribution The distribution type of the shear strength Normal Lognormal None section 20 2 The distribution type None is equivalent to a zero standard deviation Shear strength model Stress tables Y C Standard Shear strength input Default Mean v Use probabilistic defaults G Advanced Shear Strength Shear Strength Advanced Pore Pressure Design value factors 1 15 1 65 Figure 4 35 Stress table sigma tau Advanced stochastic input Design value The partial factor bon used by D GEO STABILITY to reduce the unfa factors Partial vorable characteristic value of the shear strength to a safe lower limit section 20 3 6 Design value The value of the standard normal parameter Ucharac used by factors Std D GEO STABILITY to
192. given is brackets is a corrected safety factor comparison of the Uplift Van results with Finite Element method were performed and showed that D GEO STABILITY always sur estimate the safety factor So the calculated safety factor is corrected with a constant model factor with a constant model factor 6 3 3 Critical Circle for Reliability Analysis In case of a probabilistic calculation using the Reliability analysis option or the Bishop prob abilistic random field model in the Model window section 4 1 1 complementary information compared to a standard calculation section 6 3 1 is given the value of the reliability index 6 and the probability of failure see Figure 6 8 When using external water levels section 4 6 2 for probabilistic design it is possible to view the results for each level separately by using the selection list on top 98 of 264 Deltares View Results D critical Circle 19 75 000 fel 4 Xm 52 14 m Radius 22 07 m Ym 18 43 m Satety 1 35 Probabilistic beta 2 10 probability of failure 1 80E 02 X 56 475 Y 25 810 Edt Figure 6 8 Critical Circle window for probabilistic analysis 6 4 FMin Grid The FMin Grid option in the Results menu enables the user to view iso lines of the safety factor distribution on the final grid provided that the Point and or so lines option is activated This option can be found in the FMin Grid Results tab of the Project Properties window sec tio
193. he Progress of Calculation window Figure 5 5 Deltares 89 of 264 D GEO STABILITY User Manual Progress of Calculation Minimum safety factor so far 1 10 Figure 5 5 Progress of Calculation window Once the entire initial grid has been calculated for all tangent lines the program checks whether the center point grid needs to be moved only if larger than 2x2 if the option Move Grid in the Start window was enabled If the critical circle is located along either the top or bottom tangent line then D GEO STABILITY will also shift the tangent lines in order to find the real minimum safety factor It is possible to do this using the View Input window section 2 2 3 or the S ip Circle Definition option in the Definitions menu section 4 4 1 1 Note It is possible to abort the calculation by clicking the Abort button in the Progress of Calculation window This stops the calculation and an empty graphic dump file STD is cre ated indicating that no graphical results are available A message is appended to the output file STO and only the data is saved for the slip circles calculated before the calculation was aborted 90 of 264 Deltares 6 View Results 6 1 6 1 1 The options in the Results menu can be used to view the results of the performed calculations Report On the menu bar click Results and then choose Report to view a window displaying a table of the most recent calculation results Click the Print active
194. he drawing by clicking and dragging the mouse Add point s to boundary PL line Click this button to add points to all types of lines e g poly lines boundary lines PL lines By adding a point to a line the existing line is split into two new lines This provides more freedom when modifying the geometry Add single lines s Click this button to add single lines When this button is selected the first left hand mouse Click will add the info bar of the new line and a rubber band is displayed when the mouse is moved The second left hand mouse click defines the end point and thus the final position of the line It is now possible to either go on clicking start and end points to define lines or stop adding lines by selecting one of the other tool buttons or by clicking the right hand mouse button or by pressing the Escape key Add polyline s Click this button to add poly lines When this button is selected the first left hand mouse click adds the starting point of the new line and a rubber band is displayed when the mouse is moved A second left hand mouse click defines the end point and thus the final position of the first line in the poly line and activates the rubber band for the second line in the poly line Every subsequent left hand mouse click again defines a new end point of the next line in the poly line It is possible to end a poly line by selecting one of the other tool buttons or by clicking the right hand m
195. he left or right side of the geometry It is defined by an X coordinate only Note The values entered in the Geometry Limits window are ignored if they resulted in an invalid geometry Deltares 59 of 264 D GEO STABILITY User Manual 4 3 8 Points Use this option to add or edit points that can be used as part of layer boundaries or PL lines section 4 3 10 A point is a basic geometry element defined by its coordinates Since the geometry is restricted to two dimensions it allows the user to define an X and Y coordinates respectively in horizontal and vertical directions E Cancel Help Figure 4 46 Points window Note When a point is to be deleted D GEO STABILITY will check whether the point is used as part of a PL line or layer boundary If so a message will be displayed Confirm mm At least one of the selected points is used in a boundary Pl Line line Deleting such point s might result in deletion of the boundaries Pl Lines line using such point s Continue this operation Figure 4 47 Confirm window for deleting used points When Yes is clicked all layer boundaries and or PL lines using the point will also be deleted Every change made using this window Figure 4 46 will only be displayed in the underlying View Input Geometry window after closing this window using the OK button When this button is clicked a validity check is performed on the geometry Any errors encountered during this che
196. he resistance of the soil will increase Add fixed point Click this button to graphically define the position of a point that will be part of the critical slip circle Add calculation grid Click this button to graphically define the initial position of the trial grid with slip circle center points and the corresponding positions of the trial horizontal tangent lines of the slip circle Undo zoom Click this button to undo the zoom If necessary click several times to retrace each consecutive zoom in step that was made Zoom limits Click this button to display the complete drawing Undo Click this button to undo the last change s made to the geometry D GEO STABILITY User Manual Automatic regeneration of geometry on off When selected the program will automatically try to generate a new valid geom etry whenever geometry modifications require this During generation poly lines solid blue are converted to boundaries solid black with interjacent layers New layers receive a default material type Existing layers keep the materials that were assigned to them Invalid geometry parts are converted to construction elements Automatic regeneration may slow down progress during input of complex geome try because validity will be checked continuously Delete Click this button to delete a selected element Note that this button is only available when an element is selected See section 7 5 2 for more information on how using this but
197. he slip circle measurements meet expectations With a minimum safety factor of 1 10 the dike is unsafe 138 of 264 Deltares Tutorial 1 Dike reinforced with berm v Critical Circle REESE Edit r pr AA AAA DUI ed A TEEN PES ur HE S L Materials h oF E soft clay PAE C Peat Tools A Sand o t Mode A 1 Boc rr tuu titi uU uU mp Xm 46 43 m Radius 11 36 m Ym 7 71 m Safety 1 10 X 54 108 Y 12 257 E dit Figure 8 27 Critical Circle window Slip circle with lowest safety factor In this window it is also possible to see the different stress types displayed in the geometry In the Mode toolbox in the left of the screen the type of stress to be displayed can be selected see Figure 8 28 Note When the cursor is placed over one of the symbols in the stress mode toolbox a textbox will appear to remind the user on which sort of stress the symbol indicates section 6 2 Mode A Boo TA Uu uU uU Figure 8 28 Stress mode toolbox 83 Click the Shear stress button in the Mode toolbox The results window will show the shear stresses along the slip circle Figure 8 29 Deltares 139 of 264 D GEO STABILITY User Manual Shear Stress Le foe Edit A Lu AA O AA PEA ana Br PS 1 Materials R E E sor Clay LOG L Peat Tools R E Sand PE T Mode A H H Boo T TUU T uU uU Xm 46 43 m Radius 11 36 m Max stress 18 329 kN m2 Ym 7 71
198. he system and the software The Problem Description tab enables a Deltares 9 of 264 D GEO STABILITY User Manual description of the problem encountered to be added Send Support E Mail This problem report will be sent to suppaortte ideltaressystems nl ou can also send the current file as an attachment Check the checkbox below to do this Sending of the problem report with E mail is only possible if the mail program on your system iz configured as default Simple MAFI client consult your sustem administrator This will only work if your E mail program can reach external Internet E mail addresses Attach current file to mail Cancel Help Figure 1 2 Support window Problem Description tab After clicking on the Send button the Send Support E Mail window opens allowing sending current file as an attachment Marked or not the Attach current file to mail check box and click OK to send it Support Della res DeltaresSystems Rotterdamseweg 185 Phone 37 88 335 79 03 y P O Bax 177 Fax 31 88 335 81 11 4 NL 2600 MH Delft E mail supporttadeltaressystems nl System Info Problem Description Please explain your issue here gend Print SaveAs Figure 1 3 Send Support E Mail window The problem report can either be saved to a file or sent to a printer or PC fax The document can be emailed to geo support 2deltares nl or alternatively faxed to 31 0 88 335 8111 Deltares Since Janu
199. his case it is strongly advised to use the Uplift Van method The objective of this exercise is To learn how to make calculations using the Uplift Van method For this example the following D GEO STABILITY modules are needed o D GEO STABILITY Standard module Bishop and Fellenius Uplift Van model This tutorial is presented in the file Tutorial 5 sti Introduction to the case In the soil geometry Figure 12 1 the thin peat layer beneath the clay layer might have an effect on a slip failure mechanism It is possible that the soil might slip along a certain length of this peat layer When this happens describing the slip surface by a single circle would be incorrect Using the Uplift Van method the slip surface can be described by two circular slip surfaces connected by a straight slip surface This straight slip surface usually lies along the bottom of a weak soil layer The slip surface is thus described by more parameters 5 0m S PL line 2 15m AAA m ee 0 0m Figure 12 1 Geometry overview Tutorial 5 The relevant values of the soil types used in this tutorial are given in Table 12 1 Deltares 173 of 264 12 2 D GEO STABILITY User Manual Table 12 1 Soil properties Tutorial 5 Cohesion Friction angle Unsaturated Saturated unit weight unit weight pue kN m kN m Dike sand 5 39 v w 13 1298 S Pa 002 18 o on m Geometry Wizard Firstly the g
200. his file Optional Input file ASCII Contains pore pressures from MSeep Working file ASCII Contains settings data Tips and Tricks Keyboard shortcuts Use the keyboard shortcuts given in Table 2 1 to directly open a window without selecting the option from the menu bar Deltares 19 of 264 2 4 2 2 4 3 2 4 4 D GEO STABILITY User Manual Exporting figures and reports All figures in D GEO STABILITY such as geometry and graphical output can be exported in WMF Windows Meta Files format In the File menu select the option Export Active Window to save the figures in a file This file can be later imported in a Word document for example or added as annex in a report The option Copy Active Window to Clipboard from the File menu can also be used to copy directly the figure in a Word document The report can be entirely exported as PDF Portable Document Format or RTF Rich Text Format file To look at a PDF file Adobe Reader can be used A RIF file can be opened and edited with word processors like MS Word Copying part of a table AI It is possible to copy part of a table in another document an Excel sheet for example If the cursor is placed on the left hand side of a cell of the table the cursor changes in an arrow which points from bottom left to top right Select a specific area by using the mouse see Figure 2 6a Then using the copy button or ctrl C this area can be copied Co ordinate Y Co ordinate
201. his tutorial to determine the probability that the Stability of the slope is less than the required value D GEO STABILITY performs a probabilistic calculation to determine this probability Next to this it will calculate sensitivity factors that can be used in the PCRING program The objective of this tutorial is To learn how to perform a calculation using the Bishop Random Field method For this example the following D GEO STABILITY modules are needed D GEO STABILITY Standard module Bishop and Fellenius Probabilistic random field model This tutorial is presented in the file Tutorial 7 sti Introduction to the case The Bishop Random Field Method will calculate the probability of failure for each different water level To this end D GEO STABILITY requires the input of the values of model factors The most important one is the required safety factor Next to this the soil properties can be described stochastically 17 5m 6 0m 10m 8m 3m Design level 50m Figure 14 1 Geometry overview Tutorial 7 The geometry soil properties and external water levels show in Figure 14 1 are the same as Tutorial 6 Click Open in the File menu Select Tutorial 6 Click Open Click Save as in the File menu Enter lt Tutorial 7 gt as file name Click Save oe SY Deltares 193 of 264 14 2 14 2 1 D GEO STABILITY User Manual Project Model 7 Click Model in the Project menu 8 Select the Bishop prob rand
202. his version the original MProStab features for apostiori analysis are no longer supported Introduction The Bishop probabilistic random field model is applicable when the stability requirements are stated in terms of acceptable probability of failure instead of the conventional safety factors Such situations occur when a risk analysis based approach is used for the design of a struc ture involving earth slopes For example the probabilistic design of water retaining systems in the Netherlands is executed by application of the PCRing program in connection with this model for the stability of cross sections Functional performance of these systems is stated in term of accepted probabilities of flooding due to extreme high tides or river discharge or struc tural failure due to other causes among which breach triggered by embankment slope failure The Bishop probabilistic model was developed for this purpose but it has been successfully applied in various other projects Since 2003 the original MProStab is a special module of the computer program D GEO STABILITY This chapter describes only the specific extensions and differences for this module assuming familiarity with the regular D GEO STABILITY program and the concepts of probabilistic analy sis The other chapters of the D GEO STABILITY manual contain a comprehensive description of the regular D GEO STABILITY usage and backgrounds including a tutorial introduction This section deals wi
203. ible to define a fixed point that the circle must pass To find the global position of the critical slip plane it is possible to use a rather coarse grid with a sufficiently large horizontal range and also a rather coarse distribution of tangent lines with a sufficiently large vertical range To find a more accurate value for the safety factor it is possible to reduce the range and refine the distribution of the grid and tangent lines while locating them around the position of the global slip circle For more information on the theory on slip circles see section 16 2 For an example of usage see the Tutorial 1 section 8 6 Slip Circle Definition Grid left m 43000 top m 9000 sight m 51 000 v ettem m 6 000 Humber B Humber Bo Tangent line Fixed point top m 1 500 Use fixed point bottom m 4 500 10 000 Number ls 10 000 Cancel Help Figure 4 56 Slip Circle Definition window Bishop and Fellenius methods Grid X left The initial horizontal coordinate of the leftmost center point in the moving trial grid X right The initial horizontal coordinate of the rightmost center point in the moving trial grid Number The number of grid points in horizontal direction Y top The initial vertical coordinate of the highest center point in the moving trial grid Y bottom The initial vertical coordinate of the lowest center point in the moving trial grid Numb
204. ical component is part of the slip circle D GEO STABILITY will place a slice to the left and right of this vertical The moment caused by the free water on the top of both slices is calculated using the above formula Equation 16 4 The force and moment of the free water against the vertical component of the surface now also the side of a slice is not taken into account by the above formula Instead D GEO STABILITY separately calculates the horizontal free water force and the moment caused by it X Zo Z phreatic mE slice i slice i 1 slice i 1 Case 2 Water level between top and bottom surfaces Case 1 Water level above top surface triangular shape of the water pressures trapezium shape of the water pressures Figure 16 3 Horizontal water pressures due to free water acting on the side of a slice in case of vertical layer boundary If the phreatic line is above the top surface the shape of the horizontal water pressures against the side of the slice is trapezium case 1 in Figure 16 3 H H H Mwaterside Utop H 4 y Zon T ZN x 9 bot Utop z Zn T 3 16 5 If the phreatic line is between the top and the bottom surfaces the shape of the hori zontal water pressures against the side of the slice is triangular case 2 in Figure 16 3 H H M water Side 9 Ubot 2 Zin zs 16 6 where H is the height of the saturated soil along the vertical layer boundary H min Zoned Zion
205. ically divides the slip plane into slices in accordance with the follow ing criteria Within one slice there are no intersection points of layer boundaries and or PL lines o Within one slice there are no intersection points of layer boundaries and the phreatic line The entire base of any slice which is part of the slip circle is located totally within one soil layer and completely above or below the phreatic line In addition D GEO STABILITY follows the following procedures in case a slide plane intersects the soil surface at more than two points This is possible with a ditch as well as with a dike In this case the largest area between two intersection points is taken to be the slide plane If the plane cuts the surface of the geometry at only one point the plane is rejected and is not processed any further This latter case may occur when the geometry has not been defined wide enough so that slide planes reach the outer boundaries of the geometry or when the slide planes just touches the surface at one point 16 2 Circular slip plane Bishop and Fellenius The Bishop and Fellenius method both consider the driving moments by soil weight water pressures and loads around the center of a slip circle Stability requires that the sum of these driving moments is equal to a certain resisting moment The resistance moment is generally determined by the shear strength of the soil along the slip Deltares 203 of 264 16 2 1 16 2 1
206. ight The X coordinate of the right slip circle Uplift Van E The Z coordinate of the slip circle Bishop Fellenius Ze lett The Z coordinate of the left slip circle Uplift Van Zesright The Z coordinate of the right slip circle Uplift Van Probabilistic P required The required value for the safety factor Z The limit state function Z Fs Frequired pla The mean value of parameter x o x The standard deviation of parameter x quantifying the uncertainty V The coefficient of variation V c a y x P x gt Uehara The probability of exceeding a characteristic value P amp a Tohara 1 P S Paaa o Wenge The probability that parameter x does not exceed a characteristic value charac On Qc x lt eae PN u x du 00 ynu Standard normal probability density exp u 2 ex lu PP w 2 270 x Foartial The partial factor used to reduce characteristic strength values to safe low values I The reliability index 8 LE P required o F connected to the probability of failure y 8 P E lt T enuen Design point The most likely set of parameter values with Fs Frequired Oli The influence factor for parameter x describing the sensitivity of 8 of 264 the limit state function for parameter variation weighted by the stan dard deviation alzi 55 eo EET DELIS Deltares 1 9 1 10 General Information Getting Help From the Help menu choose the Manual option to open the User Manual of D G
207. igure 3 3 Program Options window General tab Start up with Click one of these toggle buttons to determine whether a project should be opened or initiated when the program is started No project Each time D GEO STABILITY is started the buttons in the toolbar or the options in the File menu must be used to open an existing project or to start a new one Last used project Each time D GEO STABILITY is started the last project that has been worked on is opened automatically New project A new project is created The user is offered three options at the start up of D GEO STABILITY New Geometry new Geometry wiz ard and Import geometry Note that this option is ignored when the program is started by double clicking an input file Save on The toggle buttons determine how input data is saved prior to calcula Calculation tion The input data can either be saved automatically using the same file name each time or a file name can be specified each time the data is saved Use Enter The toggle buttons allow the way the Enter key is used in the program key to either as an equivalent of pressing the default button Windows style or to shift the focus to the next item in a window for users accustomed to the DOS version s of the program Program options Locations Deltares 25 of 264 D GEO STABILITY User Manual Program Options View General Locations Language Modules Working directory C Program Files Deltar
208. il Type Defaults 74 Bano DEN xx 0 3 3 m8 x Ww BOE UM wow om EON wi ud 75 45 3 1 Nails Geometry lll ee 75 4 5 3 2 Nails Nail Type rns 76 4 5 3 3 Nails Lateral Stress 0 76 4 5 3 4 Nails Shear Stress 71 TUE INDE so kee E CR AAA 78 4 6 1 Unit Weight rrr n 78 4 6 2 External Water Levels 78 4 6 3 Degree of Consolidation 80 Deltares 8 Deltares Contents 46 4 UseMSeepnet 2 2 2 2 80 4 7 Loads menu 2 a a 81 AD LneLONO 2222585523 See RRR ew Se ewe ee 81 4 7 2 Uniform Loads a a a a 82 4 7 3 Earthquake aoaaa ss A os 83 ATA TreeonSlope a 84 Calculations 85 5 1 Calculation Options aoao aoa a a a 00 a a 85 5 2 Start Calculation a a 86 5 2 1 Grid based calculation o oo aoa oa a a a a 0 000002 a 86 5 2 2 Genetic Algorithm based calculation 87 5 3 Error messages o o o on s ew ES son 89 5 4 Progress of Calculation 2 0 a a lll 89 View Results 91 6 1 Report 4A29 gt 91 6 1 1 Report Safety factor table long report 91 6 1 2 Report Information about critical slip plane 92 6 1 3 Report Extensive information about critical planes long report 93 6
209. ion Log normal Distribution Normal bi Log normal Cancel Help Figure 4 5 Probabilistic Defaults window Deltares Input Coef of var The coefficient of variation equals to the standard deviation divided Std dev mean by the mean value partial The partial factor used to reduce characteristic values to safe low values Std dev The standard deviation of a parameter quantifying the uncertainty Distribution The distribution type of a parameter Log normal lognormal probability distribution Normal standard normal probability distribution None zero standard deviation mean The mean value of a parameter 4 1 3 Project Properties On the menu bar click Project and then choose Properties to open the input window The Project Properties window contains six tabs on which allow then settings for the current project to be changed Note It is recommended to specify the settings in the Project Properties before inputting the data into the file The settings can be changed at any time It is also possible to save the setting as default defining the settings the same each time D GEO STABILITY is run Project Properties Identification Use the dentification tab to specify the project identification data Project Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Tile Tutorial 1 for D Geo Stability 0000000 Til
210. irst plane is used If the number of Transversal grid points is more than 1 both planes are used The shape of the generated slip planes depends on the selected search routine in the Start Calculation window section 5 2 If Grid based routine is chosen both defined slip planes are used to generate a multi tude of slip planes presupposing the shape of the slip plane see below If Genetic algorithm is chosen both defined slip planes are used to search for the slip plane with the least resistance without presupposing the shape of the slip plane Generated slip planes for Grid based routine Between each corresponding set of points a transversal grid line is drawn indicated in the picture below as a dashed line The given number of points is generated equally distributed along the dashed line including the points on both planes In the picture below the number of transversal grid points is 3 This means that a third plane is used lying exactly between the two planes entered The planes that are generated by D GEO STABILITY are drawn as dotted lines in Figure 4 59 Figure 4 59 Definition of slip planes The slip planes that are generated by D GEO STABILITY consist of all combinations of lines between points on subsequent transversal lines This means that if there are three corre sponding sets of points i e the table contains of three rows and the number of transversal grid points is 3 the number of generated slip plane
211. is Deltares 75 of 264 D GEO STABILITY User Manual 4 5 3 2 Nails Nail Type Nails Options for all nails Critical anale deg 5 DO Mail name Mall 2 Mail 3 Add Insert a Delete Rename y Use defaults Length nail Diameter nail Diameter grout Yield force nail Plastic moment nail Bending stiffness nail El Use facing or bearing plates 4 5 3 3 Nails Lateral Stress Geometry Nail Type Lateral Stress Shear Stress Use defaults Length nail m 20 00 Diameter nail rn AS Diameter grout rn 013 Yield force nail kN 1000000 00 Plastic moment nail kNm 5 30 Bending stiffness nail El Mme 2 64E 01 OO Use facing or bearing plate Figure 4 69 Nails window Nail Type tab Mark this check box to use the nail type defaults previously de fined in the Nail Type Defaults window section 4 5 2 Enter the length of the nail Enter the diameter of the nail Enter the diameter of the grout of the nail Enter the yield force in tension of the nail f obtained from a uni axial tensile test and used in Equation 16 25 and Equa tion 16 26 Enter the plastic moment of the nail Enter the bending stiffness of the nail Mark this check box if a facing or bearing plate is used This input is used for the calculation of the distance Lshear used to determine Tmax the ultimate frictional resistance to pull out between ground and bonded length in Equation 16 16 The
212. iw Minimum Entree Used Minimum Entree iv Maximum Entree Used Maximum x Entree e to Figure 5 1 Calculation Options window Requested number D GEO STABILITY uses the requested number of slices to determine of slices the maximum width of a slice At first slice boundaries are put on points such as geometry points or intersections between circle and layers Slices exceeding the maximum width will then be divided into smaller ones The default number of slices is 30 This is a reasonable number for a calculation Minimum circle Only available for Bishop Uplift Van and Bishop Probabilistic Ran depth dom Fields models section 4 1 1 In order to avoid slip circles with near zero soil volumes it is possible to enter a significant value for the minimum vertical depth D GEO STABILITY will only consider the slip circles with a depth exceeding this minimum Start value safety Only available for Bishop and Uplift Van models section 4 1 1 factor D GEO STABILITY uses this value as the start value for the iterative determination of the final safety factor Remolding Only available for Zone Plot model section 4 1 1 Reduction fac reduction factor tor applied on the sliding force of the ground to take into account the ground deformation due to the deformed slip surface For back ground information refer to section 22 2 Based on tests and litera ture the default value is set to 0 5
213. ke the standard colors used to display layers with their layer colors it is possible to define different colors used when displaying materials To change the color assigned to a material right click the material box The menu from Figure 7 6 is displayed Properties Material Colors Layer Numbers Material Numbers v Material Names Figure 7 6 Legend Context menu for legend displayed as Materials When selecting Material Colors the Color window appears Figure 7 7 in which the user can pick a color or even define customized colors himself by clicking the Define Custom Colors button TT ENHH PTL Ls AM Wl Hl HEE ana SEH 11 OEE ET Ft T EN E EEE PIE uo 240 fer Define Custom Colors gt gt 11 Figure 7 7 Color window 7 4 Geometry modeling 110 of 264 Deltares 7 4 1 Graphical Geometry Input Create a new geometry There are two ways to create a new geometry without the wizard Open the Geometry menu and choose New Open the File menu and choose New In the New File window displayed select New geometry and click OK see section 3 1 In both cases the Geometry tab of the View Input window is displayed Figure 7 8 with the default limits of the geometry from 0 to 100 m 9 View input 57 ES Geometry Input Edit A 20 lo X 45 500 Y 5 000 E dit Current object None Figure 7 8 View input window Geometry tab 7 4 2 Set limits 7
214. l Table 8 1 Soil properties Tutorial 1 Cohesion Friction angle Unsaturated Saturated unit unit weight weight kN m deg per Soft Clay 8 o BemSad J2 832 198 a Sad 0 X 12 e 18 to country Safety factors usually depend on the type of soil structure and its location In the tutorials in this manual soil structures with a safety factor lower than 1 15 are considered unsafe Soil structures with a safety factor higher than 1 35 are considered safe Creating a new file using the Geometry Wizard Firstly the geometry of Figure 8 1 needs to be inputted in D GEO STABILITY This basis of ge ometry can easily be created in D GEO STABILITY using the Geometry Wizard In the Wizard also basic soil layer properties can be assigned When the Wizard is completed modifica tions to complete the geometry can be made using the Edit toolbox which will be available in the View Input window This will make the geometry complete To create a new file follow the steps described below 1 Start D GEO STABILITY from the Windows taskbar Start Programs Deltares Systems D GEO STABILITY D GEO STABILITY 2 Click File and choose New on the D GEO STABILITY menu bar 3 Select New geometry wizard Figure 8 2 to use the geometry wizard to create the dike geometry and click OK New File Geometry C New geometry mport geometry Cancel Help Figure 8 2 New File window The Wizard will now
215. lane Summation of the hydraulic pressure U and the excess pore pressure By double clicking on a certain slice a special window is displayed containing detailed infor mation on that slice as shown in Figure 6 6 Slice Result slice number 5f X middle m 52 451 Safety factor 1 465 Phi 22 000 Cohesion kN m 30 000 Shear stress kN m 30 625 Weight kN 259 734 Total pore pressure kM m 113 751 Print Figure 6 6 Slice Result window Deltares 97 of 264 D GEO STABILITY User Manual 6 3 2 Critical Plane Uplift Van and Spencer On the menu bar click Results and then select the Stresses option to open the Critical Plane window which gives access to various graphical representations of the calculated results for Uplift Van or Spencer method Key information like the safety factor are printed in the status panel at the bottom jaa Slip Plane 10 x Edit E 10 Toplaag E 9 Zand los E 8 Zand keiig y Mai mm 6 Klei siltig E 5 Zand los C 4 Klei sittig LL 3 Zand los J 2 Zand kleiig 7 1 Pleistoceen IW E SERAT 68 081 E et 65 a 65 to pt td Ern p n n ra ra PE SL E i et Pal ST bs reds Xm 5 75 m Radius 6 34 m Ym 0 66 m Safety 1 57 1 50 X 14 018 Y 1 821 Zoom rectangle Figure 6 7 Critical Plane window for Uplift Van method Refer to section 6 3 1 for a detailed description of this window Note For Uplift Van method the safety factor
216. le to open the input window for forbidden lines either using the button at the left of the View Input window section 2 2 3 or from the Menu bar section 2 2 1 click Definitions and then choose Forbidden Lines D GEO STABILITY uses forbidden lines as a constraint during the automatic determination of the critical slip circle The slip circle is not allowed to intersect with the forbidden line A forbidden line can be used for example to model a sheet piling By clicking Forbidden Lines in the Definitions menu the Forbidden Lines window see Figure 4 62 will allow the addition of a forbidden line in the geometry This is done by entering the relevant coordinates in the right part of the window It is also possible to modify existing forbidden lines Forbidden Lines Co ordinates Line number 2 co ordinate at start m Y co ordinate at start I 0 000 A co ordinate at end 120 000 d Inset Inset Y co ordinate at end 0 000 Delete Cancel Help Figure 4 62 Forbidden Lines window Zone Areas for Safety This option is available only if the Enable check box in the Zone Plot sub window of the Model window is marked section 4 1 1 The Zone Plot option allows defining different zones in the dike body with a different safety factor The limits of those different zones and there corresponding safety factor can be inputted in the Zone Areas for Safety window Zone Areas for Safety Zone and 2 Zone 3 Diketable height
217. lements will be displayed as solid blue lines Valid constructions elements are converted to geometry elements as soon as the geometry is re generated For more information on adding lines and poly lines see section 7 4 Assumptions and restrictions During geometrical modeling the program uses the following assumptions Boundary number 0 is reserved for the base A soil layer number is equal to the boundary number at the top of the layer The boundary with the highest number defines the soil top surface A material soil type must be defined for each layer except for layer 0 base Different layers can use the same material All the boundaries must start and end at the same horizontal coordinates Boundaries should not intersect but they may coincide over a certain length All horizontal coordinates on a boundary must be ascending that is the equation X 74 1 X 7 must be valid for each following pair of X coordinates vertical parts are allowed PL lines may intersect and may coincide with each other over a certain length PL lines and layer boundaries may intersect All PL lines must start and end at the same horizontal coordinate gt ooo gt 002020 must be valid for each following pair of X coordinates no vertical parts allowed One way for inputting geometry data is through the Geometry menu as explained in the Reference section section 4 3 This section describes an other way to create a
218. lete Rename Cancel Help Figure 4 31 Materials window for Standard stochastic input Only the stochastic parameters are described in the paragraph For the description of the material parameters refer to Materials Input of fixed parameters section 4 2 3 1 Shear strength Selected a shear strength model from the drop down list model Shear strength Use one of the following type of input parameters either by default as input defined in section 4 1 1 or by specific selection mean values or design values Use probabilis Select this option when D GEO STABILITY should allow user defined val tic defaults ues for stochastic data section 4 1 1 Also unselect this option when D GEO STABILITY should derive stochastic data from the last two columns of a stress table When the option is reselected the defaults will over write all user defined stochastic data for this soil type Standard Select the advanced button to access both regular and special shear Advanced strength parameters mean The mean value of a parameter section 20 3 1 design The design value of a parameter section 20 3 6 Std dev The standard deviation of a parameter section 20 3 2 Distribution The distribution type of a parameter Normal Lognormal None sec Deltares tion 20 2 A distribution type None is equivalent to a zero standard devi ation 49 of 264 D GEO STABILITY User Manual Hydraulic pressure The hydraulic pressure d
219. level 6 that reduces the exceed ing frequency with a factor 10 This value varies in the Netherlands roughly from 0 3 m to 1 m See section 20 4 5 Equation 20 23 Exceeding The exceeding frequency for the design level P h gt hgdesign See frequency section 20 4 5 Equation 20 23 Level The external level connected to the hydraulic field that is defined by the PL lines at the top and bottom of each layer Deltares 79 of 264 D GEO STABILITY User Manual 4 6 3 Degree of Consolidation Choose the Degree of Consolidation option from the Water menu to model excess pore pres sures by soil weight see Figure 4 74 Degree of Consolidation J Use under overpressures above phreatic line Effect of layer ENS on consolidation of layers i Degree E E Cancel Help Figure 4 74 Degree of Consolidation window consolidation by soil weight Use under over Activate this check box to use positive or negative excess pore pres pressures above sures above the phreatic line the phreatic line Effect of layer Select the layer that causes excess pore pressures in the layers be low Degree of Specify the relative degree of consolidation AU per layer This is consolidation the relative amount of the total vertical stress by the weight of the se lected layer that is assumed to be carried as effective vertical stress by the soil skeleton A degree of consolidation of 096 means no addi tional effective stress A degree
220. limit without actually being on a limit Figure 7 13 gives an example on the left geometry 1 the end of the line seems to coincide with the boundary However zooming in on the point geometry 2 on the right reveals that it is not connected to the boundary Therefore the geometry is considered invalid Figure 7 13 Example of invalid point not connected to the left limit It is possible to correct this by dragging the point to the limit while the specific area is Zoomed in or by selecting the point clicking the right hand mouse button choosing the Properties option in the pop up menu section 7 5 3 and making the X coordinate of the point equal to the X coordinate of the limit Deltares 113 of 264 7 4 5 7 5 7 5 1 D GEO STABILITY User Manual Add piezometric level lines Ex It is possible to use the button Add PL line s to add PL lines When adding a PL line D GEO STABILITY imposes the limitation that the subsequent points of the PL line have an in creasing X coordinate Furthermore the first point of a PL line is to be set on the left boundary and the last point on the right boundary It is possible to change the position of the different points of a PL line by dragging the points as explained in section 7 5 4 or by editing the PL line This is done by selecting the PL line clicking the right hand mouse button and choosing the Properties option in the pop up menu section 7 5 3 Graphical manipulation Selection
221. lly check the points coordinates Deltares 149 of 264 D GEO STABILITY User Manual 9 4 Soil properties As explained in introduction the shear strength model for the top layer Soft clay shall be described by the undrained cohesion 17 18 19 20 21 Click Materials in the Soil menu Select Soft Clay From the drop down menu at Shear strength model choose Cu measured as the undrained cohesion at the top and the bottom is known section 9 1 Enter the suggested values for Cu At the top of the clay layer Cu top is lt 6 0 KN m gt At the bottom of the clay layer Cu bottom is lt 8 0 kN m gt Click OK Materials Total unit weight HIST RESI aaa kien 14 00 Medium Clay Below phreatic level kN rr 1 4 00 Stiff Clay F Shear strength model Cu measured Cu top kM rr 16 00 Undetermined Cu bottom kN r 18 00 Add Insert Delete Rename y Cancel Help Figure 9 5 Materials window 9 5 Definitions The safety factor of the dike has to be determined considering the left side of the dike To this end the calculation grid is placed on the left side of the dike 22 23 24 29 Make sure the nput tab in the View Input window is active Select the calculation grid It will turn red Right click and then select Properties Enter the coordinates as shown in Figure 9 6 Click OK 150 of 264 Deltares Tutorial 2 Unsaturated soil Slip Circle Definition Grid left m
222. low which has a thickness larger than zero and a PL line number not equal to 99 If the interpolation point is located above the phreatic line the pore pressure is assumed to be zero or a capillary pressure depending on the sign of the PL line number E y 2 z Vee dr wm Zphreatic wm 2 d E 18 1 where Zphreatic S the level of the phreatic line see section 18 1 z isthe hydraulic head at position x z derives from the user defined PL lines per layer section 4 3 13 in m Vw is the unit weight of water in KN m The following options are available therefore for giving PL line numbers Positive integer Capillary pore pressures are not used that is if negative pore pres sures are calculated for points above the phreatic line they become zero Zero _ All points within the layer obtain a pore pressure 0 kN m o 99 The pore pressure depends on the first layer above and or below the point with a PL line number unequal to 99 Deltares 229 of 264 18 3 D GEO STABILITY User Manual PL line 2 SAND CLAY SAND 2 1 99 1 SAND Figure 18 1 PL lines per layer Pore pressure due to degree of consolidation The degree of consolidation determines which part of the effective weight of an overlying soil layer is carried by effective stress and which part by excess pore pressure This degree ranges between 0 and 100 The effective weight o of layer is equal to Po
223. ltares Vil D GEO STABILITY User Manual et MOUT rocoso 9X 5 amp 3 een eeeenwee de eee eo 198 15 2 2 Project Properties 198 15 3 Zone Areas for Safety a a a a a a 198 15 4 Rest slope of the soil materials 199 15 5 Calculation and Results a a a a a a a a a 200 15 5 1 Safety Factor per Zone 200 15 5 2 Stresses per Zone a 200 15 6 Conclusion uu ck ean xo b ee aw ee tens A 201 16 Method of slices 203 16 1 Method of slices a 203 16 2 Circular slip plane Bishop and Fellenius 203 16 2 1 Driving moments eae ee oe ee ee aaa vos oo o o s 204 16 2 1 1 Driving soil moment 204 16 2 1 2 Driving water moment 205 16 2 1 3 Driving load moment 207 16 2 2 Resisting moments 207 16 2 2 1 Resisting moment from soil 207 16 2 2 2 Resisting moment from geotextiles 208 16 2 2 3 Resisting moment from nails 209 16 2 2 4 Resisting moment from end section 214 16 2 3 Safety factor ee ee 214 16 2 4 Limited inclination ofthe slip plane 216 16 2 5 Search algorithm for critical circle 216 16 3 Uplift Van W O a 217 16 4 Spencer MR E MW 1 ww sl
224. lute value of the total driving moment There is no iterative process for the s and Fellenius methods In such cases therefore only the total available resisting moment is displayed Division of this moment by the total driving moment immediately produces the safety factor 92 of 264 Deltares View Results If geotextiles were used and were active for the critical slip circle extra information is displayed about the contribution of the geotextile s to the resisting moment In case of a probabilistic design the probability of failure and the corresponding reliability index are written additionally to the mean value of the safety factor In case of a probabilistic design with different water levels the results for all separate levels are first presented followed by the integrated probability of failure at the design point level Report Extensive information about critical planes long report If the Long report option is selected when starting a calculation section 5 2 a large number of calculated values for the slices of the critical slide plane are displayed in three tables The values presented in these tables depend on the calculation method used The following column headings are possible Ste CEL Horizontal coordinate at center of slice Vertical coordinate at the center of the bottom of slice Y top m Vertical coordinate at the center of the top of slice 2 geom etry surface Width of slice
225. m m 75 000 0 000 75 000 Xm 0 000 34 500 40 500 50 500 0 nil 58 500 RENE b A Co EE Y Co ordinate m 0 000 pen 75 000 0 000 75 000 0o00 2 000 75000 2 0001 m 000 17000 nui E OUI 0 000 4 000 75 000 4 000 34 500 40 500 c d Figure 2 6 Selection of different parts of a table using the arrow cursor To select a row click on the cell before the row number see Figure 2 6b To select a column click on the top cell of the column see Figure 2 6c To select the complete table click on the top left cell see Figure 2 6d In some tables the button Copy is also present at the left hand pane Command line There are two tools available for processing large amounts of D GEO STABILITY calculations and producing graphical output Batch processing and Plot 20 of 264 Deltares Getting Started Batch Processing Batch Processing of D GEO STABILITY is possible by using b as a command line parameter whether or not followed by a second parameter The second parameter has multiple options the name of an inputfile the name of a folder In each of the accounts the program is closed after the last calculation has been made When the second parameter is left out e g C Program Files Deltares DGeoStability DGeoStability exe b a dialog box is shown see Figure 2 7 enabling the user to choose which folder has to be used for processing This folder can be typed in the Com
226. mbers v Show grid iw Points lw Loads Iw Forbidden lines W Snap to grid 0 250 As material numbers E Grid distance m f As material names lw Layers Selection 2 00 Accuracy 2 Save as default Cancel Help Figure 4 7 Project Properties window View Input tab Info bar Mark this check box to display the information bar at the bottom of the View Input window Legend Mark this check box to display the legend with soil types Layer Colors Mark this check box to display each soil layer using a different color It is recommended that this option is deselected if printouts are to be photo copied or faxed Rulers Mark this check box to display the horizontal and vertical rulers Same scale for Mark this check box to use the same scale for the horizontal and vertical x and y axis directions Origin Mark this check box to display the origin Large cursor Mark this check box to use the large cross hair cursor instead of the small one Points Mark this check box to display geometry points Loads Mark this check box to display loads in the nput tab of the View Input window Forbidden Mark this check box to display forbidden lines Lines Geotextiles Mark this check box to display geotextiles Labels Mark the check box of the elements Points Loads Forbidden Lines Geotextiles and Layers to display the labels of this element 34 of 264 Deltares Layers Show Grid Snap to Grid Grid Distanc
227. meters The larger the number of tests the smaller the coefficient of correlation among estimates of expected mean values of the parameters Calle 1990 Correlation can be taken into account in the Bishop probabilistic model The assumption of zero correlation however is slightly conservative Failure mechanism probability of slope failure The Bishop probabilistic random field model assumes a failure mode and equilibrium analysis of the Bishop type i e circular failure modes and the method of slices is used for equilibrium analysis In the conventional deterministic analysis it is assumed that soil data are constant in the along slope direction and that failure modes are of infinite width As a consequence no shearing forces in the cross sectional plane of slope must be considered in the equilibrium analysis In the probabilistic model itis assumed that shearing strength of the soil may fluctuate stochas tically from one cross section to another in the along slope direction Consequently the re sulting safety factor will be a stochastic function in the along slope direction Strictly speaking the assumption of absence of shearing forces in the cross sectional plane is no longer valid unless it is assumed that failure modes behave as perfectly rigid 3 D bodies Such assump tion is only justifiable if the width of a failure mode initially equals the width of a stretch where the safety factor is less than 1 0 Calle 1985 The occurren
228. modeling and using three inputted c 7 curves the measured values Tmeas the characteristic valueS 7Tchar o the mean values Tmean 19 4 1 Local measurements The pseudo characteristic value for the shear stress 7 ochar at the bottom of slice in layer 7 IS Tijipchar LL mo 1 65 x e XO te 19 4 and the pseudo measured value for the shear stress 7 5meas at the bottom of slice in layer 7 is Tij meas Tij pmeas X Tij pchar 19 5 Tij char where pri is the average shear stress determined from a test boring and inputted in the fourth column of the Sigma Tau Curves window see section 4 2 1 2 c r is the standard deviation of the tangential stress oO A A 7i Tij char J 1 65 Tij char Is the characteristic value of the shear stress determined from a test boring and inputted in the third column of the Sigma Tau Curves window see sec tion 4 2 1 2 It corresponds with the 5 lower limit Es is the pseudo characteristic factor for layer 7 o T J o T oT is the standard deviation of the total shear stress J o T J 225a 0 5 o T The standard deviation of the shear stress in layer o T3 5 ligo Tig NI is the number of layers that are cut by the slip circle n is the number of slices in layer 7 Tij meas S the measured shear stress inputted in the second column of the Sigma Tau Curves window see section 4 2 1 2 236 of 264 Deltares 19 4 2
229. n 4 1 3 This plot is only drawn if the number of grid points is less than 11 for both the X and Z directions For larger grids only the minimum value is drawn in the grid 9 Fivin Grid la Edit A 1 i Lu i i 1 L 1 1 1 1 T T PR DL RE 19 5 E JB ny Tools amp Te 95 E 1 191 1 129 1 107 1 151 1 156 1 142 E Ho tin 1 1 125 1 105 3 TM 153 1 173 1 163 e o tot 1 1 104 1 11 2 p T pr 191 1 189 Ba ta th A da 1 104 T T 159 duct 211 1 219 z5 at nor 1 116 ii 1 256 705 1 e zr y it 296 als Hi les Af 4l 1 on 347 Ls p 1 132 1 183 es E H S tr i ss RE ve xm 46 43 m Radius 11 36 m Max isoline 1 41 No of isolines 11 Ym 7 71 m Safety 1 10 Min isoline 1 10 X 49 440 Y 10 899 E dit Figure 6 9 textitFMin Grid window Deltares 99 of 264 6 5 6 6 D GEO STABILITY User Manual Safety Factor per Zone In case of a Zone plot calculation section 4 1 1 click the Safety Factor per Zone option in the Results menu to open the Safety Factor per Zone window This window shows a diagram of the Safety factor Model factor vs the Entry point active circle i e X coordinate for the calculated slip circles of each zone Mark and unmark the six check boxes at the right side of the window to show the desired zones 1a 1b 2a 2b 3a or 3b The horizontal black lines in the diagram correspond to the required safety factors of each zone as defined in the Zon
230. n 4 6 Loads Options for input of distributed surcharge and earth quake coefficients section 4 7 Calculation Determine the stresses along the critical slip circle or a user defined slip plane for a selected design analysis type chapter 5 Results Graphical or tabular output of the safety level and stress components along the slip plane Graphical output of the influence factors chapter 6 Tools Options for editing D GEO STABILITY program defaults section 3 2 14 of 264 Deltares 2 2 2 Getting Started Window Default Windows options for arranging the D GEO STABILITY windows and choosing the active window Help Online Help options section 1 9 Detailed descriptions of these menu options can be found in the Reference section The icon bar Use the buttons on the icon bar to quickly access frequently used functions see below D e Bb Ez wa E Figure 2 4 D Geo Stability icon bar Click on the following buttons to activate the corresponding functions Start a new D GEO STABILITY project B Open the input file of an existing project E Save the input file of the current project tl Print the contents of the active window Display a print preview of the active window Open the Project Properties window Here the project title and other identification data can be entered and the View Layout and Graph Settings for the project can be determined otart the calculation EEN Display the contents of online Hel
231. n and Results cllc llle 179 12 7 4 Stresses EB O a a 179 12 7 2 FMin Grid WA UI 180 128 Conclusion WA AZ ww lll l l 180 13 Tutorial 6 Reliability Analysis 181 13 1 Introduction to the case creen 181 13 2 Model Moo MD a aaa 182 13 3 Probabilistic Defaults 5 5 182 13 4 Soil EB o 183 13 5 Geometry WEBB 222 loose 185 13 5 1 Pots 222r onn e 185 13 5 2 AERE WM dd a 186 13 5 8 PL lines per Layer 187 13 6 Way NR ce ee ee a a 187 13 7 Calculation and Results 0 0 00 0000000 eee ee a 189 13 7 WMliesses Bo 189 13 7 2 FO A a 191 13 7 3 Influence Factors a a 191 138 Conclusion Wu eee id a A Aaa 192 14 Tutorial 7 Bishop Random Field Method 193 14 1 Introduction to the case a a 193 142 FIO s 2 Eon ada AAA 194 14 2 1 Model 000000 nedam ad kaeaea 194 14 2 2 Project Properties os ew 9 ox omm ee Oe 9 o o X we wo 194 14 3 Model Factor osos xoc ee KE ow d mo X 9 X X3 E X Xo OE eee De 194 14 4 Calculation and Results 2 ee a a 195 14 5 Conclusion 2 2299 9 9x9 oxRoo 63 XXX XO ox X oro X eS 196 15 Tutorial 8 Zone Plot 197 15 1 Introduction to the case creen 197 TAE PODI 2 46 68 62 Ghee Eee Eee 40x ew x 4 d ws 198 De
232. n be used to make specifications concerning water related properties in the project 4 6 1 Unit Weight Choose the Unit Weight option from the Water menu to modify the default unit weight of water see Figure 4 72 Unit Weight of Water Unit weight of water kN m3 Cancel Help Figure 4 72 Unit Weight of Water window 4 6 2 External Water Levels Input of external water levels is only required for stochastic modeling of external water level and the associated hydraulic pore pressure field in combination with either the Reliability Module or the Bishop probabilistic random field module On the menu bar click Water and then select the External Water Levels option to open the External Water Levels window see Figure 4 73 In the window that appears mark the Use water data check box in order to activate the option for stochastic modeling After that it is possible to enter all the required data D GEO STABILITY can determine the conditional probability of failure for a maximum of five different external water levels and then apply a Gumbel distribution assumption for the water level in order to determine the integrated probability This probability is determined at a certain external level called the design point See section 20 4 5 for background information 78 of 264 Deltares Input External Water Levels W Use water data later level Exceeding frequency Design level m 4 00 1440000 1 2000 C 14000 1
233. n color indicates the area with a safety factor greater than 1 35 the red color indicates an area with a safety factor below 1 15 and the orange color indicates an area with a safety factor in the range between 1 15 and 1 35 In this way it is possible to get an idea of areas that are more sensitive and less sensitive to instability A large part of the study area of the dike has a safety factor lower than 1 15 which through the definitions in the preferences window is regarded as unsafe E Safety factor 1 15 1 35 X 56 694 wags Edit Figure 8 31 Safety Overview window See section 6 8 Safety Overview for a detailed description of this window Deltares 141 of 264 8 9 8 9 1 D GEO STABILITY User Manual Berm construction The result of the calculation is a minimum safety factor lower than 1 15 this usually means that the dike is considered unsafe In order to improve the dike s stability it is proposed to construct a berm structure at the right side of the dike The general measurements of the proposed berm are depicted in Figure 8 32 17 5m 6 0m 10m 8m 3m Figure 8 32 Construction of a berm Tutorial 1b Before adding a berm to the current project a new file is created 86 Save the current file as lt Tutorial 1b gt using the Save As window of the File menu 87 Click Save Berm inputted graphically The berm will be made using the soil Berm Sand previously defined in section 8 5 Using
234. n the nail and the slip circle in kN m The soil plastification occurs at x D EE 16 18 Es The limit shear force is therefore Fo gt X pu X D x Lo 16 19 where Du is the ultimate lateral stress In D GEO STABILITY it can either be user defined if Input of ultimate lateral stress along nail is selected in the Soil Re sistance window Figure 4 2 In this case p is determined using the table inputted in the Lateral Stress tab of the Nails window Figure 4 70 using distance Lo automatically calculated by the program if Use soil parameters c phi cu is se lected in the Soil Resistance window Figure 4 2 In this case the program uses the following empirical formulas depending on the shear strength model in KN m 3o x afin K Y hi model O wi forc i models Du 1 sing diu 9 Su for s models D is the borehole diameter in m Lo is the reference length in m defined as LEN Tue 0 E L is the length from failure surface to head nail in m 212 of 264 Deltares 16 2 2 3 3 16 2 2 3 4 Method of slices Tensile and shear resistance of the nail The maximum shear stress criterion also known as Tresca s criterion predicts that failure of a ductile material e g nail in this case occurs when the maximum shear stress Tmax at a given point in the nail reaches the yield shear stress 7 obtained from a uni axial tensile test Tmax Ty 16 20 With respect
235. nate pairs c7 and 7 are required Furthermore the input values of both c7 and 7 must be monotonically increasing D GEO STABILITY always extends the curve with a last horizontal branch In the Bond Stress Diagrams window it is possible to specify different bond stress diagrams Figure 4 17 gives an example of a user defined bond stress diagram x Bond Stress Diagram 00 0 Alg Zand 0 30 Sigma ultimate Tau ultimate kN n kN n b 0 00 0 00 100 00 50 00 800 200 00 100 00 Tau ultimate kN rrr 00 500 1000 1500 2000 Sigma ultimate kN m Add a elete en e Import OK Cancel Help Figure 4 17 Bond Stress Diagrams window Import predefined Diagrams Alternatively it is possible to use predefined bond stress diagrams To do so place a DAT file with bond stress data called BondStressDiagrams in the D GEO STABILITY Install directory When clicking the Import button the Import Stress Table window appears Figure 4 18 This window contains predefined Sigma Tau curves for different kind of soil Import Stress Table Cancel Help Figure 4 18 Import Stress Table window After selecting the desired curve and clicking OK this curve is added to the others manually inputted curves in the Bond Stress Diagrams window Figure 4 19 42 of 264 Deltares Bond Stress Diagrams Curve name d Insert Delete Hename Sigma ultimate kM Aro
236. nd manipulate geometry graphically using the tool buttons of the View Input window View Input Window 104 of 264 Deltares All X coordinates on a PL line must be strictly ascending that is the equation X 7 1 gt X 2 7 3 1 Graphical Geometry Input General To use the View Input option click the Geometry tab to activate it in the regular View Input window or use the menu to select it 61 000 Er Edit Current object None Figure 7 1 View Input window Geometry tab When the Geometry tab in the View Input window is selected it displays a graphical repre sentation of only the geometrical data On the left of the window the Edit and Tools buttons are displayed section 7 3 2 On the right the legend belonging to the geometry is displayed section 7 3 3 At the bottom of the window the title panel and the info bar are displayed The title panel displays the project titles defined using the Properties option in the Project menu The info bar provides information from left to right about the current cursor position the cur rent mode and the object currently selected The legend title panel and info bar are optional and can be controlled using the Properties option in the Project menu section 4 1 3 Itis possible to use three different modes when working in the Geometry tab of the View Input window Select The Select mode is the default mode and enables the user to select existing elements in the window Th
237. ndow Hereafter is only the output in the Short Heport is described Theoutput type can be selected in the Start window see Figure 6 2 The short report gives the following intermediate data for each of the water levels and each of the circles that were analyzed X Y Radius The dimension of the slip circle Mean Value The reliability index 6 resulting from a linearization at the mean value of all parameters Design point The reliability index 6 resulting from a linearization at the so called design point in a FORM analysis e dede de ide cdd dedi d idco aie hie ee Seat aie ket dd dod dodo do dodo dedo dodo dedos ak bps Ont ee i one eat odo dedo ake ake be aiy dodo ode AA The input has been tested and 1s correct eso 2808880008 de dede dede de de dede de de dede de de ide de decode de dede de de dede de de dede de de de de dede de de de de de dede de de de de de de de de de de desde de de de dede de de de de dede de de de de dede de de de dee BESULIS OF THE SLOPE STABILITY ANALYSIS Hd Bishop Mean value Design point 060 4 86511 6 40548 767 48014 6186893 608 B6026 64752 531 54311 22246 4862 21245 83405 467 85042 36482 578 34184 66883 467 21011 398642 0867 89895 48710 782 49445 60730 6193 872686 68361 545 57733 29004 84 22122 85765 467 85731 38527 576 34881 69168 263 1325 41787 115 34071 63655 803 53015 68761 e44 30456 81345 567 63301 38757 502 20647 95951 475
238. ndows 7 32 bits H Windows 7 64 bits O Windows 8 Hardware specifications 0 1 GHz Intel Pentium processor or equivalent 512 MB of RAM 400 MB free hard disk space SVGA video card 1024 x 768 pixels High colors 16 bits CD ROM drive Microsoft Internet Explorer version 6 0 or newer download from www microsoft com OoOaqda0 To display the D GEO STABILITY Help texts properly the Symbol True Type font must be installed on the system 6 of 264 Deltares General Information 1 8 Definitions and Symbols coordinate system The horizontal axis is defined as the X axis The vertical axis is defined to be the Z direction Upward is positive and downward negative Perpendicular to the cross section is the Y Deltares direction X Geometry A iE Surface level ter Phreatic level Z piezo Piezometric level also called hydraulic head Soil material C Cohesion Bu Undrained shear strength Su bottom Undrained shear strength at the bottom of the layer Su gradient Gradient in shear strength over the depth of the layer Su top Undrained shear strength at the top of the layer POP Pre overburden pressure Us Degree of consolidation ratio in percent between the excess pore pressure and the vertical total stress increment both in layer 2 by addition of layer 7 p Friction angle of shearing resistance sat Unit weight of saturated soil below the phreatic line Yunsat Unit weight of unsaturated soil above the phreatic line
239. ne Definition window Tutorial 4a 165 Deltares List of Figures 11 14 Slip Plane window Tutorial 4a 166 11 15 Slice Result window for slice 57 Tutorial 4a 166 11 16 Stresses in Geometry window Tutorial 4a 167 11 17 View Input window Input tab Suggested second slip plane Tutorial 4b 168 11 18 Slip Plane Definition window Tutorial 4b 168 11 19 Slip Plane window with lowest safety factor found by Spencer model Tutorial 4b 169 11 20 Start window Tutorial Ac a a a a 170 11 21 Options Genetic Algorithm window Tutorial 4c 170 11 22 Slip Plane window with lowest safety factor found by Spencer model using a genetic algorithm Tutorial 4c a ee 171 12 1 Geometry overview Tutorial 5 173 12 2 New Wizard windows lll lll ll n 174 12 3 View Input window Geometry tab 175 12 4 Materials window 1 ee 176 12 5 Points window 2 2 2 2 2 2 2 2 25 52 52 5 177 12 6 Pl Lines window 489 MI 177 12 7 PL Lines per Layer window 5 5 cr 178 12 8 Slip Plane Definition window 178 12 9 View Input window Inputtab lol lr 179 12 10 Slip Plane window 2 2 2 2 2 5 5 180 12 1
240. ne plot Enable Cancel Help Figure 10 2 Model window Select Geotextiles in the Reinforcements menu 10 11 Click on the Add button The geotextile will automatically be given number lt 1 gt Enter the characteristic values given in Table 10 1 which describe the geotextile Fig ure 10 3 Click OK 154 of 264 Deltares Tutorial 3 Geotextile Geotestile number Effective tensile strength kN m 200 00 co ordinate at start m 20 00 Y co ordinate at start m 0 50 co ordinate at end m 48 00 Y co ordinate at end m 0 50 Add Insert 4 Delete Reduction area m 0 50 Cancel Help Figure 10 3 Geotextiles window see section 4 5 1 Geotextiles for a detailed description of this window In the View Input window the inputted geotextile is represented in purple see Figure 10 4 D Input Edit z N Cw A ot Y P P E O edi EE E dus Iv 4 50 i Current object None Figure 10 4 View Input window Deltares 155 of 264 D GEO STABILITY User Manual 10 4 Calculation and Results 13 Click Start in the Calculation menu to perform the calculation 14 Click Stresses in the Results menu to open the Critical Circle window Figure 10 5 15 Check that the safety factor is 1 56 Adding the geotextile results in an increase of the safety factor from 1 10 Tutorial 1a to 1 56 The dike can be con
241. ne the safe area in the Safety Overview plot Fail lt Enter the values that define the failure area in the Safety Overview plot Project Properties General The General tab allows defining general output preferences Deltares 37 of 264 D GEO STABILITY User Manual Project Properties Identification View Input Stresses Results FMin Grid Results Safety Results General Loads Size 2 00 v Lise default size Save as default Cancel Help Figure 4 11 Project Properties window General tab Labels Select the units for output of results Size Define the load size in the geometry plot 4 1 4 View Input File On the menu bar click Project and than choose View Input File to display an overview of the input data The data will be displayed in the D GEO STABILITY main window Click on the Print Active Window icon to print this file 4 2 Soil menu The Soil menu can be used to enter the soil properties for the analysis On the menu bar click Soil to display a menu with the following options for definition of soil type parameters section 4 2 1 Sigma Tau curvesto import or enter stress tables H section 4 2 1 1 for traditional deterministic design H section 4 2 1 2 for reliability based design and pseudo values O section 4 2 1 3 for reliability based design and pseudo values section 4 2 2 Bond Stress Diagrams to define friction curve at the interface between the soil and the nail section 4 2 3 Ma
242. ng nail is selected Refer to sec tion 4 5 3 3 for the input of this curve H the lateral stress is automatically determined by the program using the soil parameters if option Use soil parameters c phi CU is selected Refer to section 4 2 3 6 for the input of the extra soil paramaters needed o In Pull out sub window the shear stress along the nail can either 0 be defined as a stress curve distance from nail head vs ultimate stress for each nail if option nput of ultimate lateral stress along nail is selected 0 be defined as a bond stress diagram normal ultimate stress on vs shear ultimate stress 7 for each soil type if option Input of bond stress diagram sigma tau is selected Soil Resistance Dowel action Input of ultimate lateral stress along nail Pull aut nput of ultimate shear stress along nail fe Input of bond stress diagram sigma tau Cancel Help Figure 4 2 Soil Hesistance window Default Shear Strength Choose one of the following methods for entering the default shear strength model 30 of 264 Deltares Input C phi Use by default the input of cohesion and internal friction angle Stress tables Use by default the input of user defined Sigma Tau curves These curves relate the effective normal stress along a slip plane directly to the shear strength Cu calculated Use by default the input of the ratio between undrained cohesion and pre consolidation stress Cu measured Use
243. ngineering services and software Deltares Systems has developed a suite of software for geotechnical engineer ing Besides software Deltares Systems is involved in providing services such as hosting on line monitoring platforms hosting on line delivery of site investigation laboratory test re sults etc As part of this process Deltares Systems is progressively connecting these services to their software This allows for more standardized use of information and the interpreta tion and comparison of results Most software is used as design software following design standards This however does not guarantee a design that can be executed successfully in practice so automated back analysis using monitoring information are an important aspect in improving geotechnical engineering results Deltares Systems makes use of Deltares s intensive engagement in R amp D for GeoBrain Geo Brain s objective is to combine experience expertise and numerical results into one forecast using Artificial Intelligence Neural Networks and Bayesian Belief Networks For more in formation about Deltares Systems geotechnical software including download options visit www deltaressystems com Rijkswaterstaat DWW The Road and Hydraulic Engineering Division Rijkswaterstaat DWW of the Dutch Ministry of Transport Public Works and Water Management is the advisory division for road and hydraulic engineering related to technology and the environment It researches ad
244. nt 20 After selection it should be covered by a red square 14 To change its position click the right hand mouse button and select Properties 15 In the window displayed Figure 9 3 modify the coordinates of point 20 according to Ta ble 9 1 148 of 264 Deltares Tutorial 2 Unsaturated soil Table 9 1 X and Y coordinates of the consecutive points of the phreatic line m me 0 2 178 24 night Point 20 mm x co ordinate m 0 000 Y co ordinate m 0 000 Z co ordinate m 0 000 Cancel Figure 9 3 Point 20 properties window 16 Repeat this for points 22 21 27 26 and 25 consecutively It is not possible to move a point horizontally beyond the adjacent points otherwise an error message appears That s why the coordinates of the points must be changed from the right point 22 to the left point 25 The new shape of the phreatic line is shown in Figure 9 4 D View Input o E e Geometry Input Edit A ETT is nara lo tii H O 19 wos 18 nir 20 wi 25 tui 29 MERETE 5 nari o nari nt wi e narii 55 weit po MERETE es nari 79 nari 78 nari e m Materials fin ls Y Z7 Berm Sand 3y E Soft Clay ed E Peat D e E Sand y y Tools A n os a x 60 000 Y 10 250 E dit Current object None Figure 9 4 View Input window Geometry tab New phreatic line Note The coordinates can also be changed by dragging the points It is advised to individu a
245. nt Enter the plastic moment of the nail nail Bending stiff Enter the bending stiffness of the nail ness nail El Use facing or Mark this check box if a facing or bearing plate is used bearing plates 74 of 264 Deltares Input 4 5 3 Nails In this window the characteristic s of the nail and the lateral and shear stresses curves at the interface soil nails can be defined For background information see section 16 2 2 3 Options for all nails Critical angle The critical angle of the nail Qriticai Depending on the value of a the angle between the nail and the tangent line along the circle where the nail intersects the slip circle compared to Qcriticai the lateral or shear forces of the nail can be neglected For more information refer to Equa tion 16 12 and Equation 16 13 4 5 3 1 Nails Geometry Nails Options for all nails Critical anale deg 5 DO i Geometry Nail Type Lateral Stress Shear Stress Mail name 2 co ordinate head rr 4 000 Mail 2 Mail 3 Y co ordinate head rr 1 1 000 Horizontal spacing m 1 000 Angle with x axis deg E 50 00 Add Insert a Delete Rename y Cancel Help Figure 4 68 Nails window Geometry tab X coordinate head The horizontal coordinate of the head of the section Y coordinate head The vertical coordinate of the head of the section Horizontal spacing The horizontal spacing between two nails Angle with x axis The angle with the vertical ax
246. nternal friction angle a direct relationship between shear stress and normal stress can be applied by entering a so called sigma tau curve Alternatively it is possible to use an undrained cohesion s either by direct input of the measured value or by input of the ratio with the pre consolidation stress It is possible to combine layer with different models 1 3 2 Loads D GEO STABILITY provides the following options for defining loads Pore Fluid load Separate piezometric level lines can be specified to determine hydrostatic pore pres sures distributions and the phreatic level in each layer The volumetric weight of water can be adjusted It is also possible to include the effect of suction above the phreatic line in calculations Excess pore water pressures can be defined with piezometric level lines or with a degree of consolidation per soil layer It is also possible to use an external file containing a net of nodes in which the pore pressure is known generated with the water flow model MSeep Permanent and temporary surcharges Permanent point loads can be positioned anywhere in the geometry Distributed loads can be positioned as permanent or temporary loads very short loading time on the surface of the soil structure For these loads an angle of dispersion can be defined while a degree of consolidation must be specified for the temporary loads Earthquake In order to simulate the effects of an earthquake certain coefficient
247. oad acting between entry and exit point of the slip circle is taken into account in the load moment For background information see section 17 2 Load name Uniform Load 2 Uniform Load 3 Uniform Load 4 Uniform Load 5 Add Insert Delete Rename Magnitude kM m2 115 00 S co ordinate at start m 26 00 A co ordinate at end m 20 00 Distribution deg 45 00 Load type ad E Permanent Temporary Use under overpressures du above phreatic line Cancel Help Figure 4 78 Uniform Loads window Magnitude Theloadsizeforeachunitofarea 11111 Magnitude X coordinate at start X coordinate at end Distribution The X coordinate of the starting point of the distributed vertical load The upper X coordinate of the ending point of the distributed vertical load The angle that defines the assumed load distribution relative to the Load Type vertical direction of the load 0 lt lt 90 Select Permanent if this load should not cause any excess pore pres sures Select Temporary if it does do 82 of 264 Deltares Input Degree of In case of Temporary load specify the relative degree of consolida consolidation tion per layer This is the relative amount of the total vertical stress by loading that is assumed to be carried as effective vertical stress by the soil skeleton A degree of consolidation of 0 means no addi tional effective stress A degree of consolidation of 1
248. oceen sand Stiff clay Undetermined Add Insert a Delete Rename y Cancel Help Figure 11 6 Materials window Database tab 15 As the soil type already exists an Information window opens asking if the existing local properties should be overwritten Figure 11 7 Confirm by clicking Yes Information O Material name in use overwrite B Cancel Figure 11 7 Information window 16 Repeat it for the five other materials 17 In the Parameters tab check that the imported properties are the same as in Table 11 1 Figure 11 8 Deltares 161 of 264 D GEO STABILITY User Manual Materials Parameters Database Material name Pleistoceen sand Total unit weight Clayey sand did Above phreatic level kM rn 118 00 Below phreatic level kM rrr 20 00 Shear strength model Default C phi Cohesion c kN re 10 00 Friction angle phi deg 27 00 Dike sand Add Inzert 4 Delete Rename v Cancel Help Figure 11 8 Materials window Parameters tab 18 Click OK 11 2 5 PL lines per layer In the current file two piezometric level lines are drawn PL line 1 is the phreatic level Some of the layers have a different PL line The bottoms of layers 2 and 3 have PL line 2 as their piezometric level 19 Click PL lines per Layer in the Geometry menu 20 Enter the PL line numbers as given in Figure 11 9 21 Click OK PL lines per Layer Layer PL line PL
249. odule The background on the random field model for the drained shearing strength parameters will be discussed in detail hereafter The Bishop probabilistic random field model applies a lognormal probability distribution in combination with a certain auto correlation function to define the stochastic model for both the drained cohesion c and the tangent of the internal friction angle tan y Lognormal distribution If parameter y ln x has a normal distribution y y then parameter x has a lognormal distribution A lognormal distribution yields always positive values The normal and lognor mal distributions are similar for small ratios between the standard deviation and the mean c x u x The model derives y and e y from the user input of x and c x using equations Equation 20 2 and Equation 20 3 21 1 21 2 Auto Correlation Function The Bishop probabilistic model describes the pattern of fluctuation within a soil layer as a weak stationary random function in space This means that in each spatial point of the layer the actual shear strength parameter value is considered to be a sample realization of a random variable Weak stationary means that for any two spatial points X1 Y1 24 and 2 Y2 29 and z being the horizontal and y the vertical spatial coordinates the marginal probability 252 of 264 Deltares Bishop probabilistic random field distributions are identical and that the correlation among the ran
250. of Figures 2 1 2 2 2 3 2 4 2 5 2 6 cd 3 1 3 2 3 3 3 4 3 9 3 6 3 8 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 4 9 4 10 4 11 4 12 4 13 4 14 4 15 4 16 4 17 4 18 4 19 4 20 4 21 4 22 4 23 4 24 4 25 4 26 4 27 4 28 4 29 4 30 4 31 Deltares Deltares Systems website www deltaressystems com Support window Problem Description tab Send Support E Mail window Modules window 2 2 2 2 22 2525 2525 5 5 D Geo Stability main window D Geo Stability menu bar D Geo Stability icon bar a View Input window lt lt ew xo as AAA Selection of different parts of a table using the arrow cursor D Geo Stability batch processing window New File window 1 ee a a Program Options window View tab ee ll Program Options window General tab Program Options window Locations tab Program Options window Language tab Program Options window Modules tab Error Messages WINd0OW a a a About D GEO STABILITY window Model window Amo WM a a a a Soil Resistance Window Measurements window ee a E a Default Input Values window 2 1 e Probabilistic Defaults window a
251. of elements After selecting a geometry element it is possible to manipulate it In order to be able select a geometry element the select mode should be active Then it is possible to select an element by clicking the left hand mouse button To select a layer click on the layer number material number or material name depending on the option chosen in the Properties dialog in the Project menu When successfully selected the element will be displayed highlighted for example a point will be displayed as a large red box instead of a small black box The following remarks are relevant to selection accuracy and ambiguity Accuracy The program draws a circular selection area around the mouse pointer If the element falls within this circle it will be selected when click the left hand mouse button is clicked Fig ure 7 14 Mo selection line selected Figure 7 14 Selection accuracy as area around cursor The Selection accuracy determines the required distance between the mouse pointer and the geometrical element for selection lt is possible to use the Properties option in the Project menu to modify the accuracy section 4 1 3 This is defined in percentages of the screen size and its default value is 2 If a larger percentage is defined this increases the selection area However if the percentage is set to a relatively high value the accuracy required for the selection of certain geometry items may be inaccurate In other words it will m
252. of this MGeobase database must be first specified 9 In the Program Options window from the Tools menu select the Locations tab 10 Mark the Use MGeobase database check box and click the Browse button to specify the location of the MGeobase database with material data 11 In the Open project database window displayed select the MDB file named lt Tutorial 4 mdb gt located in the Examples folder where the program was installed 12 Click Open and then OK Program Options View General Locations Language Modules lu Save last used current directory as working directory Working directory C Program Piles DeltaresDGeoStability Projects E Iw Use MGeobase database MGeobase database C Proaram FilesD eltaressD GeoStability Projects E OF Cancel Help Figure 11 5 Program Options window Locations tab 11 2 4 Materials The soil properties of each material given in Table 11 1 can now be imported from this MGeobase file 13 Open the Materials window from the Geometry menu and select the Database tab 14 Select Clayey sand in the Materials list at the right of the Database tab and click the button to import this soil type with associated properties in the material list of the Materials window Figure 1 1 6 160 of 264 Deltares Tutorial 4 The Spencer Method Materials Parameters Database Material name Pleistoceen sand Materials Dike sand Dike sand 2 Dike sand Peat Pleist
253. olidation window 24 Select Effect of layer number 5 and change the degree of consolidation in layer 3 to 8096 and in layer 2 to 6096 according to Table 11 2 25 Click OK to confirm and close the window 11 2 7 Loads A temporary uniform load at the foot of the dike shall be applied to the dike structure In order to input these loads perform the following steps 26 Make sure the nput tab in the View input window is selected Click the Add uniform loads button 27 In the Load name sub window click Add D GEO STABILITY gives a default name Uniform Deltares 163 of 264 11 3 1 D GEO STABILITY User Manual 28 29 30 31 32 Load 1 to the load Rename it with lt Temporary load gt Fill in lt 25 kN m gt for the magnitude of the load Fill in lt 9 0 m gt for the X coordinate at start and lt 14 0 m gt for the X coordinate at end In the load type section select Temporary Click OK to confirm Uniform Loads Load name Magnitude kN m2 125 00 IN co ordinate at start m EN pl E BE 4 A co ordinate at end m i 400 Distribution deg 10 00 Load type _ Add ser 8 Permanent Temporary Use under overpressures kd Delete Rename above phreatic line Cancel Help Figure 11 11 Uniform Loads window Note In the right section of the Uniform Loads window Figure 11 11 it is possible to assign a degree of consolidation to the soil layers as a result of the uniform load
254. om field method 9 Click OK Model Model Default shear strength Bishop f Spencer Fellenius Uplift Yan f Uplift Spencer f Horizontal balance Reinforcements Reliability analysis E E zone plot Cancel Help Figure 14 2 Model window 14 2 2 Project Properties 14 3 10 11 12 On the menu bar click Project and then choose Properties to open the Project Properties window Fill in Tutorial 7 for D GEO STABILITY gt and Bishop Prob Random Field model for dike body gt for Title 1 and Title 2 respectively in the dentification tab Click OK Model Factor The required safety factor for which probability is to be established can be entered 13 14 15 16 Click Model Factor in the Soil menu to open the Model Factor window Enter 1 35 for the Limit value stability factor This is a realistic value to consider a slope as safe Leave the other values unchanged Figure 14 3 Click OK 194 of 264 Deltares Tutorial 7 Bishop Random Model Factor Limit value stability factor Standard deviation for limit value stability Factor Reference standard deviation for degree of consolidation Length of the section J Use contribution of end section 0 00 0 25 Cancel Help Figure 14 3 Model Factor window oee section 4 2 4 Model Factor for a detailed description of this window 14 4 Calculation and Results To start the calculation 17
255. omparison with another analysis e g Bishop with grid is always advised 61 Click OK to perform the calculation 62 Click Stresses in the Results menu to open the S ip Plane window 9 Slip Plane ol Se Edit 5 Materials m hme 33 Dike sand p E E Dike sand 2 Tools E Stiff clay op E Peat Clayey sand Moda __ Pleistoceen sand Bos tuu MTM A O ee Safety 1 10 X 25 502 Y 45 734 Edit Figure 11 22 Slip Plane window with lowest safety factor found by Soencer model using a genetic algorithm Tutorial 4c This slip plane is unconstrained and the limit equilibrium method guarantees the equilibrium of all forces The calculated safety factor is 1 10 Conclusion D GEO STABILITY uses the Spencer method to calculate minimum safety factors with uncon strained or user defined slip planes It is also possible to add uniform loads and attribute degrees of consolidation to soil layers due to the influence of either loads or other soil layers Deltares 171 of 264 D GEO STABILITY User Manual 172 of 264 Deltares 12 Tutorial 5 The Uplift Van model 12 1 In this tutorial a soil structure beneath which some of the layers have low weight and low cohesion is considered This situation might cause a non circular slide plane to come into effect In addition some of the layers have a different piezometric level than the phreatic line This might cause a portion of the layers to be lifted Therefore for t
256. on and friction angle This can be done with or without using the probabilistic defaults In this tutorial the design value factor for the friction angle of Berm Sand must be changed 18 Select Berm Sand in the materials list 19 Deselect Use probabilistic defaults 20 Inthe right part of the window select Advanced 21 Now select the Shear Strength Advanced tab 22 Change the value of partial to lt 1 20 gt in the Phi design value factors sub window 23 Click OK 184 of 264 Deltares Tutorial 6 Reliability Analysis Materials Total unit weight alli MU Above phreatic level kN ne 19 50 i Below phreatic level kM rr 21 00 Shear strength model D efault E phi ha Standard Shear strength input D efault Mean Use probabilistic defaults Advanced Shear Strength Shear Strength amp dvanced Pore Pressure Undetermined Correlation coefficient cohesion and tan phi 10 00 Cohesion design value factors Partial 28 O Std dev 11 65 Phi design value factors Partial 11 20 Std dev 1 65 Add Insert Delete Rename Cancel Help Figure 13 6 Materials window Shear Strength Advanced tab 13 5 Geometry 13 5 1 For this probabilistic calculation three possible water levels on the left side of the dike are taking into account To this end two new PL lines called MHW and MLW in Figure 13 1 have to be first inputted into the geometry Points To
257. on is deselected if printouts are to be photo copied or faxed Mark this check box to display the rulers Same scale for Mark this check box to enforce the same length scale for horizontal and x and y axis Origin Large cursor Points Loads Forbidden Lines Geotextiles Labels Deltares vertical axis Mark this check box to display the origin Mark this check box to use the large cursor instead of the small one Mark this check box to display geometry points Mark this check box to display loads Mark this check box to display forbidden lines Mark this check box to display geotextiles Mark the check box of the elements Points Loads Forbidden Lines Geotextiles and Layers to display the labels of this element 35 of 264 D GEO STABILITY User Manual Soil layers may be identified by their material name their index in the list of materials or their index in the list of layers in the soil profile Layers Project Properties FMin Grid Results The FMin Grid Results tab allows selecting the way the minimum factors of safety are repre sented in the FMin Grid results window section 6 4 Project Properties Identification View Input Stresses Resulte FMin Grid Results Safety Results General Display jw Rulers Large cursor Iw Point labels Same scale for and y axis W lsolines Lines Humber of lines If Use values fram results 11 41 li Display line numbers Save as default C
258. onal reliability index 6 and the external water level h e ss 246 21 1 Program Options window lel 250 21 2 Model window 2 2 2 2 2 2 2 2 2 2 25252 5 25 5 251 21 3 Typical pattern of spatial fluctuations of cone resistances in a soft cohesive layer253 22 1 Schematization of the zones 1A 1B 2A 2B and 3 of the zone plot method 257 22 2 Schematization of the modified slip surface deformed situation after rotation 258 Deltares List of Tables List of Tables 2 1 Keyboard shortcuts for D Geo Stability 19 4 1 Rheological coefficient and compression ratio for different soil types 56 8 1 Soil properties Tutorial 1 o 120 8 2 X and Y coordinates of the berm construction points 143 9 1 X and Y coordinates of the consecutive points of the phreatic line 149 10 1 Characteristics of the geotextile 153 11 1 Soil properties Tutorial 4 a a a a a a cll ll 158 11 2 Degree of consolidation per layer 163 12 1 Soil properties Tutorial 5 a a a a a a lll ll 174 13 1 Safety factor for different water levels 191 15 1 Required safety factors for the zone areas of the Zone Plot model 197 18 1 Different degrees of consolidation in different layers 231 Deltares xvii D GEO STABILITY Us
259. only possible to manipulate the Point number column that is the coordinate columns are purely for informative purposes To manipulate the coordinates of the points select the Points option from the Geometry menu see section 4 3 8 Every change made using this window will only be displayed in the underlying View Input Geometry window after closing this window using the OK button When clicking this button a validity check is performed on the geometry Any errors encountered during this check are displayed in a separate window These errors must be corrected before closing this window using the OK button Of course it is always possible to close the window using the Cancel button but this will discard all changes Deltares 61 of 264 4 3 11 4 3 12 D GEO STABILITY User Manual Phreatic Line Use this option to select the PL line that acts as a phreatic line see Figure 4 49 The phreatic line or groundwater level is used to mark the border between dry and wet soil Phreatic Line Select the PlLine by number which acts as phreatic line Cancel Help Figure 4 49 Phreatic Line window Select the appropriate line number from the drop down list and click the OK button At least one PL line has to be defined to be able to pick a Phreatic Line Layers This option enables the user to add or edit layers to be used in the geometry A layer is defined by its boundaries and its material Use the Boundaries t
260. ontributions to the failure resisting moment In this equation Mo denotes the overturning moment of the corresponding slip circle and I Me and oye are the expected mean value and standard deviation of the edge contribution to the failure resisting moment Deltares 255 of 264 D GEO STABILITY User Manual 21 5 4 Stochastic water level model The Bishop probabilistic random field model incorporates the uncertainty in the external water level in the same way as D GEO STABILITY s Reliability module chapter 20 256 of 264 Deltares 22 Zone Plot 22 1 22 2 This chapter describes the background of the Zone Plot module Differentiation of safety factors The zone plot method is based on the requirement that the rest profile of a dike remains always intact in case of high water turning back This rest profile is defined by see Figure 22 1 acrest of 3 meters width with a level corresponding to the dike table height DTH and an overtopping flow of 0 1 l s m an inside talus with a slope depending on the material of the dike and the underground 1 2 for clay and 1 4 for sand and peat River Polder Figure 22 1 Schematization of the zones 1A 1B 2A 2B and 3 of the zone plot method A high safety factor applies below this rest profile Zone 1 Slip surfaces which damage this rest profile must have a safety factor which is higher than or at least equal to the safety factor for macro stability recommended by the
261. oo xo RR oo ORO Rx s 20 3 4 Characteristic value from a normal distribution 20 3 5 Characteristic value from a lognormal distribution 20 3 6 Design value Probabilistic analysis 20 4 1 FORM procedure 5050888 20 4 2 Assumptions and limitations of the Reliability module 20 4 3 Stochastic hydraulic pore pressure 20 4 4 Stochastic excess pore pressure 20 4 5 Stochastic water level model 20 4 6 Stochastic model factor 21 Bishop probabilistic random field 21 1 21 2 21 3 21 4 21 9 About the Bishop probabilistic random field History vu oom a omo x om m x on v BEN oo o a OO Introduction nus s xoc oom Rx ee AE S ne 21 31 Special Files 21 3 2 Selecting the module and model Working with the model Background NIA 21 5 1 Random field model for shear strength 21 5 2 Failure mechanism probability of slope failure 21 5 3 Probabilistic analysis 21 5 4 Stochastic water level model 22 Zone Plot 22 1 22 2 Differentiation of safety factors Determination of the modified slip surface 23 Benchmarks Bibliography Deltares Contents D GEO STABILITY User Manual X Deltares List of Figures List
262. ordinate Number m m 0 000 100 000 Cancel Help Figure 7 25 PL line window Property editor of a PL line Note In the Boundary and PL line properties windows only the points number can be modified not the X and Y coordinates 7 5 4 Dragging elements Drag and drop One way to modify elements is to drag them to other locations To drag an element first select it Once the element has been selected it is possible to drag it by pressing and holding down the left hand mouse button while relocating the mouse cursor Dragging of geometry elements can result in automatic regeneration of geometry if this option is switched on section 7 4 4 as shown in the example of Figure 7 26 when the selected point is moved upwards a new geometry will be created D GEO STABILITY creates new layers according to this new geometry Before Figure 7 26 Example of dragging of a point 118 of 264 Deltares 8 Tutorial 1 Dike reinforced with berm 8 1 In this first tutorial the safety factor of a dike body which is part of a water retaining reservoir is determined and shows that the dike body doesn t meet the safety requirement Therefore a berm have to be added to stabilize it The objectives of this exercise are To learn the steps needed to set up a model geometry and calculation To learn to create soil layers and attach properties like shear strength and friction angle To perform a simple slip plane calculations
263. orizontal force Fw due to water is Ziele v Z dim X Vw F 16 44 where Zophreatic iS the vertical level of the phreatic line in m Z slip is the vertical level of the slip plane in m Vw is the unit weight of water in KN m Deltares 221 of 264 D GEO STABILITY User Manual The safety factor is where J is the total resisting force 222 of 264 16 45 Deltares 17 17 1 Loads Different kinds of loads can be applied in D GEO STABILITY section 17 1 Line load section 17 2 Uniform load section 17 3 Earthquake section 17 4 Tree on slope Line loads A line load can be placed in on or above the soil structure and is assumed to continue infinitely in the direction perpendicular to the geometry plane The angle of the load can be chosen freely as long as there is a vertical downward component The distribution angle determines the way the load spreads in the soil structure If the bottom of a slice is located within the dispersion area of the load the total stress is increased using the following formula F x sin 8 0 pum 2 x A xo 21 yo y x tan INO is the increase of the total stress at bottom of slice in KN m Ao 17 1 where F is the magnitude of the line load in KN is the angle of load with the vertical axis in degree X is the X co ordinate center of bottom of slice in m Yo is the Z co ordinate center of bottom of slice in m 21 is the
264. ost likely result in too many ambiguous selections see the following section or will make it difficult to perform an intentionally empty selection Ambiguous selection A selection of geometrical elements can be ambiguous Figure 7 15 gives an example a user may want to select a point a boundary line a boundary or a PL line As several elements are in close proximity to each other D GEO STABILITY does not automatically select an element 114 of 264 Deltares 7 5 2 Graphical Geometry Input Figure 7 15 Selection accuracy as area around cursor In this case D GEO STABILITY requires the user to assign the element that is to be selected by displaying a pop up menu Figure 7 16 with the available types of elements within the range of the selection click It is possible to select the element from this menu Select Boundary 3 Select Boundary 4 Select Boundary 5 Select Boundary Line Figure 7 16 Selection accuracy as area around cursor Clear selection lt is possible to clear a selection by clicking in an area without geometry elements in the direct area Deletion of elements A Click the Delete button to delete a selected element This button is only available when an element is selected When a point is selected and deleted it and all lines connected to it are deleted as shown in Figure 7 17 Before After Figure 7 17 Example of deletion of a point When a geometry point a point used in a b
265. otextile is used 17 5m 6 0m 10m 8m 3m Figure 10 1 Dike reinforced with geotextile Tutorial 3 Table 10 1 Characteristics of the geotextile Effective tensile strength X coordinates at start Y coordinates at start Length Deltares 153 of 264 10 2 10 3 D GEO STABILITY User Manual Project Properties In this tutorial the same file which has been created in the Tutorial 1 is used 1 Open the first tutorial by clicking Open in the File menu and selecting the tutorial named Tutorial 1a 2 Click Open 3 Save the project as a new file by clicking Save as in the File menu and by entering lt Tutorial 3 gt as the file name 4 Click Save 5 On the menu bar click Project and then choose Properties to open the Project Properties window 6 Fill in Tutorial 3 for D GEO STABILITY gt and lt Dike reinforced with geotextile gt for Title 1 and Title 2 respectively in the dentification tab 7 Click OK Geotextile To add a geotextile to the geometry do the following 8 12 Mark the Geotextiles check box in the Model window of the Project menu Model Model Default shear strength f Bishop i D phi f Spencer Stress tables f Felleniug Cy calculated f Uplift Yan Cy measured f Uplitt Spencer f Cy gradient f Bishop probabilistic random field f Pseudo values Horizontal balance Reinforcements Reliability analysis v iseatextiles M Enable Nails Zo
266. oundary or PL line is selected and deleted the program deletes the point and its connected boundary lines as shown in Figure 7 18 It then inserts a new boundary that reconnects the remaining boundary lines to a new boundary Deletion of a geometry element boundary boundary line geometry point PL line can result Before After Figure 7 18 Example of deletion of a geometry point in automatic regeneration of a new valid geometry if the Automatic regeneration option is switched on When a line is selected and then deleted the line and its connecting points are deleted as shown in Figure 7 19 In addition the layer just beneath that boundary is deleted All other line parts that are not part of other boundaries will be converted to construction lines Deltares 115 of 264 7 5 3 D GEO STABILITY User Manual A RON X b i dd Before After Figure 7 19 Example of deletion of a line Using the right hand mouse button When using the mouse to make geometrical manipulations the right mouse button enables full functionality in a pop up menu while the left button implies the default choice The options available in the pop up menu depend on the selected geometrical element and the active mode When the Select mode is active and the right hand mouse button is clicked the pop up menu of Figure 7 20 is displayed Properties Delete Undo Hedo View Prefer ences Sta
267. ouse button or by pressing the Escape key This also stops adding poly lines altogether A different way to end a poly line is to double click the left hand mouse button Then the poly line is extended automatically with an end line This end line runs horizontally from the position of the double click to the limit of the geometry in the direction the last line of the poly line was added Therefore if the last line added was defined left to right the end line will stop at the right limit Note that by finishing adding a poly line this way it is possible to start adding the next poly line straight away 106 of 264 Deltares Redo Cu Click this button to redo the previous Undo action 107 of 264 Deltares Graphical Geometry Input Add PL line s Click this button to add a piezometric level line PL line Each PL line must start at the left limit and end at the right limit Furthermore each consecutive point must have a strictly increasing X coordinate Therefore a PL line must be defined from left to right starting at the left limit and ending at the right limit To enforce this the program will always relocate the first point clicked left hand mouse button to the left limit by moving it horizontally to this limit If trying to define a point to the left of the previous point the rubber band icon indicates that this is not possible Subsequently clicking on the left side of the previous point the new point will b
268. p Display the first page of the Deltares Systems website www deltaressystems com Deltares 15 of 264 2 2 3 D GEO STABILITY User Manual View Input The View Input window displays the geometry and additional D GEO STABILITY input of the current project The window has the following two tabs Geometry In this view it is possible to define inspect and modify the positions and soil types of different layers For more information on these general D GEO STABILITY options for geometrical modeling see the description of the Geometry menu section 4 3 Input In this view it is possible to define inspect and modify the additional D GEO STABILITY specific input For more information on the available options see below in this section See also the description of the Definitions menu section 4 4 View Input ol xl Geometry Input Edit A ROS LD Vm LAA pe 1 A Om Te ene m Materialen f s RI E Dike sand Wy 9 C Dike sand 2 my O Stiff clay los Peat Y Y 45 X 110 000 Y 42 000 Edit Current object None Figure 2 5 View Input window It is possible to use the buttons on the panels at the left to control the graphical view and to add input data Click on the following buttons in the Edit and Tools panel to activate the corresponding functions Select and Edit mode M In this mode the left hand mouse button can be used to graphically select a previ ously defined grid load
269. p planes with the Spencer method These slip planes shall be defined later on in this tutorial section 11 4 1 The Spencer method ensures moment vertical and horizontal equilibrium Calculation and Results To calculate the safety factor for the slip plane that has been inputted do the following 39 Click Start in the Calculation menu Deltares 165 of 264 D GEO STABILITY User Manual 40 Click OK to perform the calculation 41 Click Stresses in the Results menu to open the Slip Plane window The Slip Plane window displayed Figure 11 14 gives a safety factor of 1 47 Slip Plane Definition M Generate slip planes Figure 11 14 Slip Plane window Tutorial 4a 42 Double click on a slice to see the results for this individual slice In Figure 11 15 the results for slice 57 are shown They include the visualization of the force balance and several values that describe the slice s geometry forces or stresses Slice Result Slice number 5f X middle m 52 451 Safety factor 1 465 Phi 7 22 000 Cohesion kN mnr 30 000 Shear stress kN m 38 625 Weight kN 259 734 Total pore pressure kN m 113 751 Print Figure 11 15 Slice Result window for slice 57 Tutorial 4a 166 of 264 Deltares 11 4 1 Tutorial 4 The Spencer Method 43 Click Stresses in Geometry in the Results menu to open the Stresses in Geometry window Figure 11 16 D stresses in Geometry I e 53 X Coordinate 4
270. plane and smaller at the passive side An average value at the horizontal part of the slip plane follows from a direct simple shear test DSS A small passive value follows from a triaxial test in extension TE A high active value follows from a triaxial test in compression TC D GEO STABILITY can model this stress induced anisotropy by assuming a shear strength that can vary not only top down Also D GEO STABILITY can define a sinus function along the orien tation of the slip plane The shear strength then varies horizontally according to this function The function along the plane is defined by the input of the average value the minimum value atthe passive side and the maximum value at the active side Figure 19 2 234 of 264 Deltares Shear Strength models Active Passive Figure 19 2 Stress induced anisotropy 19 3 Calculated undrained strength When using the shear strength option Cu calculated section 4 2 3 1 D GEO STABILITY will calculate the shear stress along the slip plane from the ratio f between the undrained co hesion and the pre consolidation stress according to the following equation Ta fou X P 19 3 where len is the ratio between undrained strength s and the pre consolidation stress P The average value of f ranges between 0 18 and 0 26 re is the vertical pre consolidation stress in kKN m P max 01 prt OFC OV ne j is the reference vertical effective stress calculated from the r
271. pletely consolidated conditions Excess pore pressures specified by this option are assumed to be perfectly spatially correlated within a soil layer and not correlated among dif ferent soil layers Deltares 245 of 264 20 4 5 20 4 6 D GEO STABILITY User Manual Stochastic water level model The Bishop probabilistic random field model determines the probability of failure given a safety factor Itcan do so for differing external water levels The external water levels provide a basis for a stochastic description of the water level The model incorporates the uncertainty in the external water level by the execution of the following steps o D GEO STABILITY determines the conditional probability of failure for different user specified external water levels and their associated hydraulic fields D GEO STABILITY combines the resulting relationship between the reliability index and the external water level using linear interpolation with a Gumbel assumption for the water level distribution This is in order to find the integrated probability of failure that is shown in the report D GEO STABILITY applies a FOSM procedure for this purpose H1 H2 H3 Figure 20 2 Linear interpolation between the conditional reliability index 5 and the exter nal water level h Equation 20 23 shows the exceeding probability for the design level according to the Gumbel distribution This distribution is determined by the Gumbel parameters B and Ugumb
272. pressed area between the active and passive slip circles The method becomes equal to Bishop s method if the length of the horizontal part reduces to zero Figure 16 10 Van Uplift Stability derivation The resulting horizontal forces at active and passive side of the compressed soil are assumed to act above the interface with the sand at 1 3 of the height of the weak soil layers Moment equilibrium around active circle center M yields Equation 16 30 for the resulting force at active side k k Ti b x Ry p yi hi bi sin a x Ry 2 4 F D H wc 16 30 where F is the safety factor that has to be determined Deltares 217 of 264 D GEO STABILITY User Manual The vertical equilibrium of slice 2 yields Equation 16 31 _ GAG x cu tang T tano x tan pi Mean Es where u is the pore pressure at the slip plane Substitution of Equation 16 31 into Equation 16 30 gives Equation 16 32 1 at y hi u tan bj k 1 114 i i 1 De y h b sina F tana x tangi tano X tan cosa Fs d ees F 16 32 l oR Equation 16 33 for the horizontal force at passive side is derived similarly a 1 C y h em uj tan Pj bj 2 1 Yj hj bj Sin Qj n F 1 2 tan Qj x tan Pj COS Qj Fs Ly H 16 33 9 Fi The horizontal shear force along the interface is described by Equation 16 34 Ts Il L 16 34 Es Substitution of Equation 16 32 Equation 16 33 and Equa
273. pth of the layer per meter Std dev The value of the standard normal parameter Ucharac used by D GEO STABILITY to calculate the unfavorable characteristic value of the undrained shear strength section 20 3 4 section 20 3 5 4 2 3 5 Materials Bishop probabilistic random field method If the Bishop probabilistic random field method in the Model window is enabled section 4 1 1 D GEO STABILITY uses stochastic values for its calculations On the menu bar click Soil and then select the Materials option to open the Materials window see Figure 4 41 In this window all data related to the soil type is entered See section 21 5 1 for background Materials Total unit weight JET Above ato leva kN mz 13 00 Clay clean moderate Sand l sil moderate Below phreatic level kN me 21 00 Cohesion c kN m 0 00 Dhc Friction angle phi deg 32 50 Dc Std dev c kM rr 10 00 M tests c 5td dev phi deg 14 88 Vert tot var c Cor c phi 10 00 Dh phi Std press pn kN frre 0 50 Dy phi Add Insert N tests phi Delete Rename Vert tot var phi m 10 75 Cancel Help Figure 4 41 Materials window for Bishop probabilistic random field method Cohesion Bishop prob random field Mean value of the cohesion Friction angle Mean value of the friction angle 54 of 264 Deltares Std dev c Std dev phi Cor c phi Std press pn Dh c Dv c N tests c Vert tot var c dh phi dv phi N tests phi
274. r 7 will be calculated but this is unrealistic To prevent this from happening the value for o is restricted to p 2 45 This means that o never obtains a value less than 2 45 To illustrate this see the following table where the 7 and restricted 7 are given for various values of o and restricted a In Figure 16 8 the value of the other parameters in the formula for 7 is as follows c 0 kN m ip 20 G 10 kN m Fy 1 The minimum value for becomes p 2 45 35 The relation plus the assumption is displayed in Figure 16 8 Angle Shear Stress relation 20 M actual value assumed value ae o fe o NI o e o al o E o oO o N eo o o h o N o Co o E o 91 o o o N e co o e eo Shear Stress kN m2 20 Angle alpha deg Figure 16 8 Relation angle a Shear Stress for o 35 Search algorithm for critical circle D GEO STABILITY applies a search algorithm that automatically moves the grid and tangent lines towards the direction of the minimal safety factor During this procedure the size of the grid is not changed This procedure can only be used when there are three or more center points in both the X and Z directions If a minimum safety factor is found that is enclosed within the grid this is not a definite guar antee that it is the absolute minimum safety factor for the problem at hand In a large grid of center points it is possible to h
275. re Deltares 189 of 264 D GEO STABILITY User Manual Materials Xm 52 14 m Radius 22 07 m Ym 18 43 m Safety 1 35 Probabilistic beta 2 10 probability of failure 1 80E 02 56 475 Y 25 810 Edit Figure 13 12 Critical Circle window The drop down menu at the top of the window can navigate between the results for the different water levels 52 Select MHW 3 50 m to display the results for Mean High Water Figure 13 13 Materials Xm 52 14 m Radius 22 07 m Ym 18 43 m Safety 1 47 Probabilistic beta 2 72 probability of failure 3 27E 03 ajea MEE EL Berm Sand E Soft Clay 58 712 i 27 126 E dit Figure 13 13 Critical Circle window for Mean High Water level As expected the safety factor 1 47 is higher than in the design case An overview of the results is given in Table 13 1 190 of 264 Deltares Tutorial 6 Reliability Analysis Table 13 1 Safety factor for different water levels Water levels Safety factor Design level 4 0 m 1 35 MHW 3 5 m 1 47 MLW 3 0 m 1 48 13 7 2 FMin Grid To view the FMin Grid window for the case that results in the largest safety factor 53 Click FMin grid in the Results menu Figure 13 14 a 518 ron IU 631 ps 636 pen I 3 544 p st pro I 552 p ys 2 hs f I5 9 ise quo f 79 pw T I wo i N N N to a Co N Co a AA A 2 n EY 8 zE i ges
276. records Geometrical objects A geometry can be built step by step through the repetitive use of sketching geometry cre ation and geometry manipulation Each step can be started by using line shaped construction elements section 7 1 2 to add line drawings After converting these drawings to valid geometry parts the specific geometry elements created can be manipulated section 7 1 1 Geometry elements A geometry can be composed from the following geometry elements Points A point is a basic geometry element defined by its coordinates As stated earlier the geometry is restricted to two dimensions allowing to define X and Y coordinates only Boundary lines A boundary line is a straight line piece between two points and is part Bens Pr Boundaries A boundary is a collection of connected boundary lines that forms CUT tne continous boundary between get nn PL lines A piezometric level line is a collection of connected straight line e Y pieces defining a continuous piezometric level Phreatic line This is a PL line that acts as phreatic line The phreatic line or groundwater level is used to mark the border between saturated and unsaturated soil Layers A layer is the actual soil layer Its geometrical shape is defined by its boundaries and its soil type is defined by its material Materials A material defines the actual soil material or soil type It contains the parameters belonging to the soil type such as its unsaturated weight
277. reep reduction factor An inversion inverts all values in a chromosome Jump mutations are efficient in a simple search space like Bishops method and Uplift Van With Spencer s method creep and inverse mutations are more likely to produce good off spring Note Spencers limit equilibrium method cannot always produce a valid result Searching in a space with a relative large number of invalid results requires a large population and generation count in order to find a good solution and will require much more calculation time Only solutions with the thrust line inside the soil body are accepted Error messages If the input contains any errors a message is displayed A description of the errors that must be corrected is located in the output file or in the error file The output file contains an echo of the input and messages concerning all errors that were found This file can be viewed with the Report option in the Results menu The Error messages option in the Helo menu allows the user to display the error messages for the last calculation performed for the current project Note To keep the messages it is only possible to print them as they will be overwritten the next time a calculation is started Progress of Calculation Critical circle search If the input contains no errors the program will start calculating all circles in the initial grid The screen displays a progress overview and the minimum safety factor found so far in t
278. resses in any vertical across the calculation domain 80 Click Results and then choose Stresses in Geometry This will produce the graphical output Figure 8 26 The blue left area represents water pressure The green right area represents the total soil pressure As expected the pore pressure is linear throughout all the layers The effective vertical stress increases linearly within each layer Deltares 137 of 264 D GEO STABILITY User Manual 9 Stresses in Geometry baks lt Coordinate 37 500 X 69 665 Figure 8 26 Stresses in Geometry window 81 Clicking the cursor anywhere in the horizontal domain will produce a representation of the stresses in the vertical at that point It is also possible to manually provide the X coordinate in the domain of which to see the stresses in the vertical at that point This X coordinate can be given in the upper left corner of the window See section 6 2 Stresses in Geometry for a detailed description of this window 8 8 3 Stresses To view the slip circle that coincides with the lowest safety factor found by the calculation 82 Choose Stresses from the Results menu to open the Critical Circle window Figure 8 27 This window shows the slip circle drawn in the geometry and includes its measurements Here it can be seen that D GEO STABILITY did not moved the grid to find the minimum safety factor the center point of the slip circle lies within the chosen grid T
279. ries to the right of the point number 45 Click the Y coordinate of point 18 and change it from value 4 0 to lt 0 25 gt cll Then to get a new shape of the phreatic line three new points are added using theAdd row button 46 Click the Add row button three times to add three new points 47 Modify the coordinates of the points 19 20 and 21 as given in Figure 8 16 below Cancel Help Figure 8 16 Points window 130 of 264 Deltares 8 4 2 Tutorial 1 Dike reinforced with berm 48 Click OK See section 4 3 8 Points for a detailed description of this window PL lines The horizontal shape of PL line 1 which represents the phreatic line is now modified by adding the three points defined before section 8 4 1 49 Click PL Lines in the Geometry menu to open the PL Lines window Figure 8 17 m By clicking the Insert Row button it is possible to enter new points in the sequence that connects the different points of PL line 1 50 Click on row number 2 51 Click the nsert Row button three times The PL line will now consist of five points Points 2 3 and 4 have to be provided 52 At the entry right of 2 enter lt 19 gt 53 Click on the row that represents point 3 54 At the entry right of point 3 enter lt 20 gt 55 Click on the row that represents point 4 56 At the entry right of point 4 enter lt 21 gt The PL lines window should now look as in Figure 8 17 4 000 4 000 3 250 0 2
280. rizontal driving soil moment due to earthquake is TV M p soil quake H ap X y Gi x Zr Zo 17 3 i 1 where Qh is the horizontal earthquake factor i e acceleration coefficient as defined in the Earthquake window in section 4 7 3 G is the weight of the soil in slice 2 see Equation 16 2 in KN m Zi eg is the vertical co ordinate of the centre of gravity of slice in m 7 m MD soit es G X bi where Mp soi is the moment of soil loads at the bottom of slice 2 from the top to the bottom of slice 2 in KNm m Refer to section 1 8 for the definition of the other symbols Additional moments due to vertical acceleration The coefficient to increase the vertical gravitation has the following influence on soil stress slice weight driving moment and water pressure Additional driving soil moment due to vertical acceleration TL MDp soil quake V Ay X y Gi X Xistop Xo 17 4 i 1 where Q4 is the vertical earthquake factor i e acceleration coefficient as defined in the Earthquake window in section 4 7 3 G is the weight of the soil in slice 2 see Equation 16 2 in KN m Refer to section 1 8 for the definition of the other symbols 226 of 264 Deltares Loads Excess pore pressure due to earthquake Earthquake forces will generate excess pore pressures in layers that are not fully drained The excess pore pressures are determined by taking into account the degree of consolidation per layer This degree of
281. rrelation function See section 21 5 1 Equation 21 4 The ratio between vertical and total variance variance is the square of the standard deviation See section 21 5 1 Equation 21 4 4 2 3 6 Materials Nails If the Use soil parameters c phi cu option in the Soil Resistance window is selected sec tion 4 1 1 D GEO STABILITY uses the following soil parameters to determine the ultimate lateral stress at the interface soil nail p using either the friction angle or the undrained cohesion of the soil depending on the Shear Strength model of the soil Pu 3 x0 x Ky with K Pu 9 X Su sno 1 siny for c phi models for Cu models the Young s modulus of the soil E using the compression ratio of the soil CR Lor C 0 and the rheological coefficient of the soil a See section 16 2 2 3 for background information Deltares 55 of 264 D GEO STABILITY User Manual Materials Total unit weight all Above phreatic level kM rr i 8 00 Clay Below phreatic level kN free 20 00 Peat Shear strength model Default C phi Cohesion c kM rr 10 00 Friction angle phi deg 45 00 Mails Use soil type Sand Compression ratio Ce e0 0 0033806 Rheological coefficient alpha 10 33 Add Insert Delete Rename v Cancel Help Figure 4 42 Materials window for nails with option Use soil parameters c phi cu Use soil type If
282. rs To assign a PL line to each layer do the following 27 In the Geometry menu choose PL lines per layer to open the PL lines per Layer window 28 Enter the PL line numbers given in Figure 12 7 for each layer 29 Click OK Deltares 177 of 264 D GEO STABILITY User Manual PL lines per Layer Layer PL line PL line Number at top at bottom BHO a E E E Cancel Help Figure 12 7 PL Lines per Layer window Due to the different piezometric levels in the soil layers the soil is prone to lifting forces This can be verified with a simple evaluation or hand calculation 126 Definitions To make a calculation with the Uplift Van model the specifications of the slip surface need to be defined To this end two grids are needed to define the slip circles on either side of the slip surface The slip surface on the left will cut the soil structure The right slip surface will cut the surface somewhere right of the soil structure Also tangent lines that connect the two slip circles need to be placed in the geometry Those lines will lie at the bottom of the weak peat layer Those connecting lines complete the total slip surface 30 Click Slip Plane in the Definitions menu 31 In the Slip Plane Definition window enter the specifications shown in Figure 12 8 Slip Plane Definition Grid left lett m 25 Dr Y top fight m 30 ooo Y bottam Number le Number Grid right left m 155 000 Y top X ight Y boattom
283. rties Figure 7 21 Clicking outside the geometry layers will display the menu with the Layer Properties option disabled as there is no layer for which properties can be displayed Deltares Delete All Loose Lines Delete All Loose Points Deltares Graphical Geometry Input This option will delete all loose lines Loose lines are actually construc tion lines that are not part of the boundaries or PL lines therefore all lines displayed as solid blue lines With this option it is possible to quickly erase all the leftover bits of loose lines that may remain after converting lines to a geometry This option will delete all loose points Layer 1 Material type Information on current material type Unit weight dry EN m3 14 00 Unit weight wet EN ms 14 00 Cancel Figure 7 21 layer window Property editor of a layer Point 17 ExS M co ordinate m 100 000 Z co ordinate m 1 000 Y co ordinate m 0 000 Cancel Figure 7 22 Point window Property editor of a point 0 000 3 093 4 000 6 421 12 767 45 570 100 000 E Cancel Help Figure 7 23 Boundary window Property editor of a polyline 117 of 264 D GEO STABILITY User Manual Boundary Line 8 Paint 5 co ordinate m I 4 000 Z co ordinate m O00 Point 13 co ordinate m 145 570 Z co ordinate m E 3b Length rn 31 me Slope I E Cancel Paint Co ordinate 2 Co
284. rview window 103 Select Safety Overview from the Results menu E Safety factor 115 135 X 77 024 Y 7 947 E dit Figure 8 37 Safety Overview window 144 of 264 Deltares 8 10 Tutorial 1 Dike reinforced with berm The window displayed Figure 8 37 shows that the full dike has a safety factor higher than 1 35 Therefore the construction of the berm has made the dike structure safer Conclusion The Geometry Wizard is one of the ways to construct a simple project geometry There are tools in the program to completely customize the geometry to specific needs Once these details have been input they can be used to calculate a range of results These include the minimum safety factor measurements of the critical slip circle and stresses along the slip circle and in any vertical in the geometry One way to view these results is to display them graphically on the screen A design conclusion is that in this case the construction of a berm has helped to increase the minimum safety factor of the dike structure Deltares 145 of 264 D GEO STABILITY User Manual 146 of 264 Deltares 9 Tutorial 2 Unsaturated soil 9 1 This tutorial continues the case in Tutorial 1 chapter 8 Here a measure is taken to lower the water level in the reservoir left of the dike In the dike itself excess pore pressures shall arise clay Pore pressures will remain high for a period of time after lowering the water level To see
285. s 219 16 5 Horizontal Balance e 221 17 Loads 223 17 1 Lineloads au WP ole 223 17 2 Uniform loads 4a E WD 224 17 3 Earthquake We Woo 226 17 3 1 Additional moment due to horizontal acceleration 226 17 3 2 Additional moments due to vertical acceleration 226 17 4 Tree on SETA A n n nnm 228 18 Pore pressures 229 18 1 Phre ii line Moo ool 4 Re 229 18 2 Hydraulic pore pressure from piezometric level line 229 18 3 Pore pressure due to degree of consolidation 230 18 4 Pore pressure from temporary distributed loads 231 18 5 Total pore pressure and effective stress 231 19 Shear Strength models 233 19 1 Stress tables 2 55 soo woo rss ew eS www we 233 19 2 Measured undrained strength 234 19 3 Calculated undrained strength 235 19 4 Pseudo values a 236 19 4 1 Local measurements e 236 19 4 2 Global measurements regional set of tests 237 20 Reliability analysis 239 20 1 Supported Methods lll lll lr 239 20 2 Stochastic distributions a a a a a a a 239 20 3 Stochastic shear strength a a a a 240 viii Deltares 20 4 ELI SIM ee RR he Ee Se eee A 20 3 2 Standard deviation 20 3 3 Stress tables uus oo ox
286. s Water Loads Calculation Results Tools Window Help DORA EG aa y ad fl View Input Geometry l Input Edit wy Wh A Ge Y 12 294 2 2 1 The menu bar E dit Current object None Figure 2 2 D Geo Stability main window To access the D GEO STABILITY menus click the menu names on the menu bar File Project Soil Geometry Definitions Reinforcements Water Loads Calculation Results Tools Window Help Figure 2 3 D Geo Stability menu bar The menu contains the following functions File Standard Windows options for opening and saving as well as several D GEO STABILITY options for exporting and printing the active window section 3 1 Project Global model selection Input of project identification and layout options for specific windows Modification of probabilistic defaults section 4 1 Soil Definition of soil type properties section 4 2 Geometry Definition of general geometrical data like layers soil types and piezo metric lines section 4 3 Definitions Definition of specific geometrical data for D GEO STABILITY models like the initial possible slip plane position geotextiles forbidden lines ref erence level et cetera section 4 4 Reinforcements Input of the geotextiles and nails section 4 5 Water Input of water weight degree of consolidation or import of pore pres sures from MSeep Input of external water levels for probabilistic design sectio
287. s can be entered to introduce additional moment and excess pore pressure and to modify the free water movement Tree on Slope The effect of wind on trees rooted in the slope can be modeled 2 of 264 Deltares 1 3 3 1 3 4 1 4 1 4 1 1 4 2 General Information Slip plane determination A limit equilibrium method like Bishop Van or Spencer determines the safety factor along a given slip plane In a geometry an infinite amount of slip planes can occur Therefore a search algorithm needs to find which slip plane is representative The default search algorithm is the grid method By defining a square with center points and a number of tangent lines all combinations of possible slip planes are investigated If the representative plane is on the edge of the grid it is an option to move the grid in that direction to ensure a minimum This grid based procedure works for all implemented limit equilibrium methods It becomes very time consuming if the search space is very large Bishop Van or if an unconstrained slip plane is sought after using Spencer s method The Genetic Algorithm offers an alternative that is faster in case of a large search space The precision of the result depends on the input parameters In short two optimization techniques are available to find the representative slip plane o the Grid method calculates all combinations of center points and tangent lines if appli cable o the Genetic algorithm find
288. s chapter are well documented in literature There are no exact solutions for these problems available however in the literature estimated results are available When verifying the program the results should be close to the results found in the literature Groups 3 4 and 5 of benchmarks will grow as new versions of the program are released These benchmarks are designed in such a way that new features specific to the program can be verified The benchmarks are kept as simple as possible so that per benchmark only one specific feature is verified As much as software developers would wish they could it is impossible to prove the correct ness of any non trivial program Re calculating all the benchmarks in this report and making sure the results are as they should be will prove to some degree that the program works as it should Nevertheless there will always be combinations of input values that will cause the program to crash or produce wrong results Hopefully by using the verification procedure the number of times this occurs will be limited The benchmarks will all be described to such detail that reproduction is possible at any time In some cases when the geometry is too complex to describe the input file of the benchmark is needed The results are presented in text format with each benchmark description The input files belonging to the benchmarks can be found on CD ROM or can be downloaded Deltares 259 of 264 D GEO STABILITY
289. s is equal to 3 27 Note Increasing those numbers results in a large increment of slip planes For example when the Interval parameter is 4 and the number of points per entered slip plane is 6 the total number of generated slip planes is equal to 4 4096 Deltares 69 of 264 D GEO STABILITY User Manual ooo BNO Figure 4 60 Typical situation of generated slip planes 4 4 2 Calculation Area Definition The following applies only when the Horizontal Balance method is selected section 4 1 1 Click Definitions and then choose Calculation Area Calculation Area Definition i co ordinate lett side m 5 00 amp co ordinate right side m 5 00 Highest slip plane level m 10 00 Lowest slip plane level m 1 00 Humber of planes in slip plane level 2 Cancel Help Figure 4 61 Calculation Area Definition window Horizontal Balance method X coordinate The horizontal coordinate of the left side of the calculation area left side X coordinate The horizontal coordinate of the right side of the calculation area right side Highest slip The vertical coordinate of the highest slip plane level plane level Lowest slip The vertical coordinate of the lowest slip plane level plane level Number of The number of planes in vertical direction between the highest and the planes in slip lowest slip plane levels plane level 70 of 264 Deltares Input 4 4 3 Forbidden lines 4 4 4 It is possib
290. s stochastic values for its calculations Sigma Tau Curves Curve name Curve 1 Btw AL Basisveen Kre l HOLLANDYVEER Add Insert Delete Rename Import Figure 4 16 Sigma Tau Curves window for Pseudo values shear strength model Sigma Tau Tau characteris tic Tau mean Number of tests Deltares Sigma Tau Curve Kr Al HOLLANDVEEN NAAST Sigma Tau Tau Tau characteristic mean EN rr EN ro EN rrr EN m Tau kin 0 0 20 0 40 0 60 0 Sigma KN m Number of tests E m Cancel Help The normal stress values of the o 7 curves The measured shear stress values drawn in black in the chart at the right of the window The characteristic shear stress values drawn in red The mean shear stress values drawn in blue Only available for Global measurements section 4 1 1 The number of tests performed to get the three inputted o r curves measured char acteristic and mean 41 of 264 4 2 2 D GEO STABILITY User Manual Bond Stress Diagrams This option is available only if the option nput of bond stress diagram sigma tau has been selected in the Soil Resistance window section 4 1 1 On the menu bar click Soil and then select Bond Stress Diagrams in order to open the Bond Stress Diagrams window The curves relate the normal ultimate stress ol sigma to the shear ultimate stress 7 tau Each curve is defined by entering successive coordinates Two coordi
291. s the representative plane through an algorithm that is more efficient in a large search space with many degrees of freedom for the slip plane Results After analysis D GEO STABILITY can present results in a tabular and graphical form The tabu lar report contains an echo of the input data concise information on all calculated slip surfaces and if required detailed information on the critical slip surface It is possible to view graphical output of the distribution of various stress components along the critical slip plane as well as view graphs of the water pressure and vertical effective stress along verticals A probabilistic analysis will yield a graph with influence factors Influence factors are in fact the result of an automated sensitivity analysis and show how much uncertainties in specific parameters contribute to the overall uncertainty in the factor safety Features in additional modules Spencer model This model is intended for special non circular stability analysis It determines a single safety factor for a user defined position of an arbitrary shaped slip surface Uplift Van model This model is intended for usual uplift stability analysis It determines automatically the lowest safety factor assuming a horizontal plane bounded by two circles Deltares 3 of 264 D GEO STABILITY User Manual 1 4 3 Reliability based design methods With D GEO STABILITY s reliability module it is easy to switch between
292. second left hand mouse click defines the end point and thus the final position of the first line in the poly line and activates the rubber band for the second line in the poly line Every subsequent left hand mouse click again defines a new end point of the next line in the poly line It is possible to end a poly line by selecting one of the other tool buttons or by clicking the right hand mouse button or by pressing the Escape key Add PL line s Click this button to add a piezometric level line PL line Each PL line must start at the left limit and end at the right limit Furthermore each consecutive point must have a strictly increasing X coordinate Therefore a PL line must be defined from left to right starting at the left limit and ending at the right limit To enforce this the program will always relocate the first point clicked left hand mouse button to the left limit by moving it horizontally to this limit If trying to define a point to the left of the previous point the rubber band icon indicates that this is not possible Subsequently clicking on the left side of the previous point the new point will be added at the end of the rubber band icon instead of the position clicked Zoom in Click this button to enlarge the drawing then click the part of the drawing which is to be at the center of the new image Repeat if necessary Zoom out Click this button then click on the drawing to reduce the drawing size Repeat if n
293. sidered safe with the geotextile kabak Materials __ Soft Clay L Peat EJ sand Det pu pls pla da sa os DID 7 Xm 46 43 m Radius 11 79 m Ym 7 71 m Safety 1 56 X 53 969 Y 12 428 E dit Figure 10 5 Critical Circle window 10 5 Conclusion D GEO STABILITY is able to make calculations incorporating a geotextile in the geometry For this the strength properties of the geotextile should be known The safety factor will increase when a geotextile with greater tensile strength is placed in the geometry 156 of 264 Deltares 11 Tutorial 4 The Spencer Method In this tutorial the safety factor of a dike with different water levels at either side is established The calculation is carried out with the Spencer method This method uses a user defined slip plane and thus requires the user to manually describe this slip plane The slip plane is of an arbitrary shape consisting of a line defined by a series of user defined points The objectives of this exercise are To learn how to import the soil type properties from an MGeobase database To learn how to assign different piezometric levels to layers To learn how to apply loads To learn how to carry out a calculation using the Spencer method To learn how to perform a calculation using a generic algorithm For this example the following D GEO STABILITY modules are needed D GEO STABILITY Standard module
294. soil skeleton A degree of consolidation of 10096 means no excess pore pressures For background information see section 18 3 Deltares 83 of 264 D GEO STABILITY User Manual 4 7 4 Tree on Slope The Tree on Slope option in the Loads menu displays an input window in which the effect of the wind in the trees can be inputted For background information see section 17 4 Force Point of application X Point of application Y Width of root zone Angle of distribution 84 of 264 Tree on Slope Wind Force kM 200 00 Point of application 1 m DES Point of application Y m 2 00 Tree Width of root zone m 110 00 Angle of distribution deg 115 0 Cancel Help Figure 4 80 Tree on Slope window Enter the magnitude of the wind force Enter the horizontal coordinate of the application point Enter the vertical coordinate of the application point Enter the horizontal width of the root zone Enter the angle of distribution of the effect of the root zone Deltares 5 1 Calculations Calculation Options On the Menu bar click Calculation and then choose Options to modify a number of settings for the analysis the number of slices the minimum slice depth and the start value safety factor Calculation Options Requested number of slices Minimum circle depth Minimum slipplane length start value safety factor Remolding reduction factor schematization reduction factor Use friction of end section
295. ssure In case this condition is not fulfilled D GEO STABILITY assumes negative correlations among the hy drostatic and the remaining pressure component in order to obtain a consistent stochastic model Stochastic excess pore pressure Excess pore pressure is caused by loading D GEO STABILITY can attribute a degree of con solidation to a soil layer D GEO STABILITY also takes into account which layer s load causes the excess pore pressure The degree of consolidation expresses the adjustment of effec tive stresses in this layer and is denoted in percentages For example 100 percent in a layer means that the weight of an predefined overlying layer is fully consolidated 0 percent means an undrained condition The estimation of excess pore pressures is often based on very rough guesses of permeability and poor calculation methods Consequently substantial uncertainties may be involved It is assumed that these uncertainties greatly overrule local fluctuations of pore pressures for example due to small scale heterogeneity of permeability In case excess pore pressures are specified in terms of degrees of consolidation a reference value for the standard deviation must be provided Oret percents The standard deviation of uncertainty of a specified degree of consolidation is calculated as pra Pas Clayer 40 ret TO X Wh 20 22 Thus standard deviations of excess pore pressures equal zero in the case of fully undrained and com
296. stability of slip circles is expressed by MR soit E MRgeotextile Rs Mr nai T Mr end Sion Mo soi T Mo water T Mo water quake zs MDp oad zm Mp soil quake 16 28 214 of 264 Deltares Method of slices with Mob soil quake M p soil quake V FJ Mb soil quake H where Mr soi is the resisting soil moment in KNm m see Equation 16 8 Mr geotextile is the resisting moment from geotextiles in KNm m see Equation 16 11 MRail is the resisting moment from nails in KNm m see Equation 16 15 Mk end section iS the resisting moment due to the additional friction caused by a limited end section of the slip plane in KNm m see Equation 16 27 only for Bishop model in combination with s shear strength models Mb soi is the driving soil moment in KNm m see Equation 16 1 Mob water is the driving water moment in kNm m see Equation 16 3 Mbp waterquake is the additional driving water moment due to the temporary draw down of the water during the earthquake in KNm m see Equation 17 7 Mb oad is the driving load moment in kKNm m see Equation 16 7 Mbssoitquake v is the additional driving soil moment due to vertical acceleration of the earthquake in kNm m see Equation 17 4 Mb soiquake H is the additional driving soil moment due to horizontal acceleration of the earthquake in kNm m see Equation 17 3 1 is the sign of Mr end section If Mp lt 0O 2 lL lf Mp gt 0 2 1 J is the sign of M bD soil quake H If Mp l
297. stress at depth z due a load see Equation 17 1 for line loads and Equation 17 2 for uniform loads 232 of 264 Deltares 19 Shear Strength models 19 1 This section gives background on the following shear strength models section 19 1 Stress tables section 19 2 Measured undrained strength section 19 3 Calculated undrained strength section 19 4 Pseudo values For a description of stochastic shear strength modelling see section 20 3 Stress tables When using the Stress Table shear strength option section 4 2 3 1 D GEO STABILITY will determine the shear strength from user supplied stress tables also called 0 7 curves sigma tau section 4 2 1 Depending on the stress situation at the bottom of a slice one of the line segments of this curve is used to find values for c cohesion and y internal friction angle In order to determine which line segment to use D GEO STABILITY uses Equation 16 9 and Equation 16 10 for the shear stress of resp Bishop and Fellenius models and Equation 19 1 for the effective normal stress F x0Gd cxtano On 19 1 F tana x tan ver where is the normal effective stress along the slip plane in KN m is the safety factor is the vertical effective stress in KN m is the cohesion in kN m is the angle of slice bottom in degree 908828 With this c value the line segment of the c 7 curve containing this value is determined and from the line segment equation
298. t 0 7 If Mp gt 0 7 1 Mb is the total driving moment without the contribution of Mb soit quake H Mp m Mo soi pP Mo water T Mob water quake UN Mbsload T Mb soil quake V Mag is the total resisting moment without the contribution of Mr end section Ma Mhnisoit Mr geotextiie Mr nail The unit kNm m indicates the moment per 1 meter of the cross section perpendicular to the cross section plane For Bishop substitution of Equation 16 9 in the expression for the safety factor Equation 16 28 yields to Equation 16 29 an expression in which the safety factor occurs at both sides D GEO STABILITY therefore determines the safety value for Bishop in iterative fashion start ing with a first estimate of the safety factor of 1 0 The result of the calculation on the left is used as a next estimate and this process continues until FN Fn 1 0 001 or a maximum number of iterations has been made in which case no result is obtained n b C 0 tan p R A EE Mhngeotextile T MR nail 1 Mr end section COS Q tan qj i 1 1 tano Doz X MD soit Sp Mo water as Mo water quake a Mbioad b MDp soil quake 16 29 Deltares 215 of 264 16 2 4 16 2 5 D GEO STABILITY User Manual Limited inclination of the slip plane In the formula for the calculation of the shear stresses 7 a problem arises for large negative values of the angle a For these negative values a large value fo
299. tability factor The required value for the safety factor P required Standard deviation for the This value expresses the uncertainty caused by the Bishop limit value stability factor model assumptions Reference standard devi The standard deviation of the reference excess pore pressure ation for degree of con ata degree of consolidation of 50 See Equation 20 22 in solidation section 20 4 3 Length of section The length of the considered section in the out of plane direc tion Use contribution of end Select this button to include the stability increase caused by section the resistance at the edges of a sliding section in the out of plane direction see section 21 5 3 Lateral stress ratio The model assumes a single value for the earth pressure co efficient 9 of all layers during calculation of the resistance at the edges A common value is 0 5 Lateral stress ratio Coefficient of variation The ratio for the moment at the edges of a section See Equa contribution edge tion 21 9 in section 21 5 3 4 3 Geometry menu The Geometry menu can be used to enter geometry specifications for the analysis 4 3 1 New Select this option to display the View Input Geometry window showing only the geometry limits with their default values of the geometry It is possible to now start modeling the geom etry However it is possible to create a new geometry faster and easier using the Geometry Wizard This wizard involves a step by step proc
300. tch Design Code TGB Geotechnical Structures Phoon K K and F H Kulhawy 1999a Characterization of geotechnical variability Can Geotech Journal no 36 625 639 Phoon K K and F H Kulhawy 1999b Evaluation of geotechnical property variability Can Geotech Journal no 36 625 639 Spencer E 1993 A method of analysis of the stability of embankments assuming parallel interslice forces Geotechnique 17 no 1 11 26 TAW 1985 Leidraad voor het ontwerpen van rivierdijken Deel 1 Bovenrivierengebied Tech rep Technische Adviescommissie voor de Waterkeringen TAW 1989 Leidraad voor het ontwerpen van rivierdijken Deel 2 Benedenrivierengebied Tech rep Technische Adviescommissie voor de Waterkeringen Uitgeverij Waltman Delft TAW 1994 Handreiking Constructief ontwerpen Tech rep Technische Adviescommissie voor de Waterkeringen Van Marcke E 1983 Random Fields Analysis and Synthesis Verruijt 1982 Collegedictaat b22 Grondmechanica CUR Civiele Technische Hogeschool Delft afdeling Civiele Techniek vakgroep Geotechniek Deltares 261 of 264 D GEO STABILITY User Manual 262 of 264 Deltares Deltares sustems PO Box 177 31 0 88 335 81 88 2600 MH Delft sales deltaressystems nl Rotterdamseweg 185 www deltaressystems nl 2629 HD Delft The Netherlands
301. ted during a previous Session For an D GEO STABILITY installation based on floating licenses the Modules window may ap pear at start up Figure 2 1 Check that the correct modules are selected and click OK Modules W D Geo Stability Standard module Bishop and Fellenius W Spencer module jw Uplift module W Relability amp nalyses module W Probabilistic Random Field module W Show at start of program Figure 2 1 Modules window When D GEO STABILITY is started from the Windows menu bar the last project that was worked on will open automatically unless the program has been configured otherwise under Tools Program Options Main Window When D GEO STABILITY is started the main window is displayed Figure 2 2 This window con tains a menu bar section 2 2 1 an icon bar section 2 2 2 a View Input window section 2 2 3 that displays the pre selected or most recently accessed project an info bar section 2 2 4 a title panel section 2 2 5 and a status bar section 2 2 6 The caption of the main window of D GEO STABILITY displays the program name followed by the model and the default shear strength names and the project name When a new file is created the default model is Bishop the default shear strength is C Phi and the project name is Project1 Deltares 13 of 264 D GEO STABILITY User Manual D Geo Stability Bishop C Phi Projecti ni xj File Project Soil Geometry Definitions Reinforcement
302. ted in the status panel at the bottom of the window Xm 46 43 m Radius 11 36 m Ym 7 71 m Safety 1 10 X 51 954 v 12 065 Edit Figure 15 6 Critical Circle window for Zone 1a See section 6 6 Stresses per Zone for a detailed description of this window 15 6 Conclusion A calculation using the Zone Plot model has been performed The body dike is divided into six parts showing the rest profile The required safety factor for many circles situated in Zone 1a is not reached Deltares 201 of 264 D GEO STABILITY User Manual 202 of 264 Deltares 16 Method of slices This c gives background information on the methods used in the current release of D GEO STABILITY Next to this the theories of shear strength model pore pressures and loads are given Exten sive attention is given to reliability based design 16 1 Method of slices For calculating slope stability D GEO STABILITY uses the method of slices This method divides the earth mass above the slide plane into a number of vertical slices see Figure 16 1 Slices For each slice the different soil parameters effective stresses and pore water pressures are calculated These values are assumed to be representative for the entire slice The method assumes a circular shaped slip plane failure mechanism with radius r d Figure 16 1 Slip plane including method of slices D GEO STABILITY automat
303. terials to define soil type properties by one of the following options H section 4 2 3 1 Input of fixed parameters for traditional deterministic design section 4 2 3 2 Import from a material library section 4 2 3 3 Input of parameter distributions for reliability based design section 4 2 3 4 Input of parameters for pseudo values shear strength model section 4 2 3 5 Input of parameter for Bishop probabilistic random field method O section 4 2 3 6 Input of parameters for the soil mails interface section 4 2 4 Model factor to define the parameters for Bishop probabilistic random field method Doucodcl 38 of 264 Deltares 4 2 1 4 2 1 1 Input Sigma Tau Curves On the menu bar click Soil and then select Sigma Tau Curves in order to open the Sigma Tau Curves window in which stress tables can be imported or entered The content of this window depends on the selected model Refer to section 4 2 1 1 for traditional deterministic design Refer to section 4 2 1 2 for reliability based design Refer to section 4 2 1 3 for reliability based pseudo values Sigma Tau Curves for deterministic design The curves relate the normal effective stress O sigma to the shear strength 7 tau Each curve is defined by entering successive coordinates A deterministic analysis requires two coordinate pairs c and T design Furthermore the input values of both o and 7 must be monotonically increasing D GEO STABILITY always extends the
304. th the following topics section 21 3 1 Special files used by Bishop probabilistic model section 21 3 2 How to select the Bishop probabilistic module and model Deltares 249 of 264 D GEO STABILITY User Manual 21 3 1 Special Files pcr Output file ASCII with sensitivity factors for PCRING 21 3 2 Selecting the module and model On the menu bar click Tools and then select Options to open the Program Options window If the D GEO STABILITY installation is based on floating licenses then it is possible to use the Modules tab to claim a license for the particular modules that are to be used This window Figure 21 1 will also be shown directly at start up as long as the Show at start program box marked Program Options View General Locations Language Modules License FlexLm Ww D Geo Stability Standard module Bishop and Fellenius i Spencer module iw Uplift module i Reliability Analyses module i Probabilistic Random Field module W Shaw at start of program Figure 21 1 Program Options window On the menu bar click Project and then select Mode to open the Model window see Fig ure 21 2 Select the Bishop prob random field option 250 of 264 Deltares 21 4 21 5 Bishop probabilistic random field Model Model Default shear strength Bishop rm r Spencer f Fellenius f f Uplift van Lg Uplift Spencer 1 Horizontal balance Reinforcements Reliability analysis
305. the Edit toolbox it is possible to represent the berm In order to do so follow these steps 88 89 90 91 In the View Input window select the Geometry tabto begin to add the berm geometry Click the Add polyline s button in the Edit toolbox located on the left of the window Draw the polyline by clicking on the places consecutively indicated in Figure 8 34 The points of the polyline can be placed at exact coordinates due to the snap to grid settings in the Project Properties window section 4 1 3 This can be achieved by checking to which coordinates the cursor will snap to this can be seen in the lower left corner of the View Input window see Figure 8 33 To finish drawing the polyline right click anywhere in the geometry X 46 500 Y 2 000 Edit Figure 8 33 Lower left corner of View Input window The coordinates of the consecutive points are given in Table 8 2 In the enclosed area the Undetermined shall appears Figure 8 34 142 of 264 Deltares Tutorial 1 Dike reinforced with berm Table 8 2 X and Y coordinates of the berm construction points Figure 8 34 View Input window Geometry tab Berm construction points To check whether the point of the new polyline has the correct coordinates do the following 92 Click on point number 11 A red square will be placed over the selected point 93 Click the right hand mouse button and select Properties In the window displayed Fig ure 8 35
306. the values for c and y are determined y is determined by the angle of the line segment while c is determined by the point where the line segment would intersect the vertical c 0 kN m axis In the first iteration o cannot be determined with the above formula because is unknown also stress dependent therefore in the first iteration g is used to determine the first estimate of c and y Deltares 233 of 264 19 2 D GEO STABILITY User Manual 45 40 35 30 25 20 Shear stress t kN m 0 20 40 60 80 100 120 Figure 19 1 Example of o r curve Figure 19 1 shows an example of a o 7 curve Such a curve is usually obtained from test results on the soil The curve obtained from the test results will normally have to be adjusted in order to include a certain degree of safety For the angle at the bottom of the slice the same restrictions apply as with the standard cal culation method explained in the section above With the c and y determined as explained above the safety factor F can be determined in an iterative process as explained in sec tion 16 2 2 1 1 Measured undrained strength When using the shear strength option Cu measured section 4 2 3 1 D GEO STABILITY will define the shear stress acting at the bottom of each slice as equal to the specified value for the undrained strength To Su 19 2 Stress induced anisotropy The shear strength in an over consolidated soil is larger at the active side of the slip
307. this check box is marked the Soil type must be specified D GEO STABILITY will automatically determine the compression ratio and the rheological coefficient using the values according to M nard and given in Table 4 1 Compression Enter the compression ratio of the soil CR C 1 eo ratio Cc 1 eo Rheological co Enter the rheological coefficient of the soil empirical parameter used efficient alpha by M nard to relate the modulus of deformation E to the pressuremeter modulus Fi Es Eon Table 4 1 Rheological coefficient and compression ratio for different soil types Soil type nheolog coefficient Compression ra ChH G c 1 T o 0 0023884 0 0039806 0 0495100 0 1287400 0 899 1000 56 of 264 Deltares Input 4 2 4 Model Factor This option is available only if the Bishop probabilistic random field method in the Model window is enabled section 4 1 1 On the menu bar click Soil and then select the Model Factor option in order to open the Model Factor window see Figure 4 43 In this window all general stochastic data can be entered See section 21 5 3 for background Model Factor Limit value stability Factor Standard deviation for limit value stability factor O08 Reference standard deviation for degree of consolidation 4 0 00 Length of the section m 1 00 00 Use contribution of end section 10 00 0 25 Cancel Help Figure 4 43 Model Factor window Limit value s
308. tine Tutorial 4c uses two defined slip planes to search for the slip plane with the least resis tance without presupposing the shape of the slip plane i e genetic algorithm Project How to define the layers geometry and soil properties has been explained already in the previous tutorials Use the different figures and data s given in section 11 1 to create the geometry and then proceed with section 11 3 for the description of the additional steps However an alternative to the manual input is to import the geometry from a so called GEO file section 11 2 1 and to import the soil properties from an MGeobase database section 11 2 3 Importing an existing geometry To import the geometry from a GEO file follow the steps below 1 In the File menu select New to open the New File window Figure 11 2 2 Select the mport geometry option and click OK f New File Geometry C New geometry C New geometry wizard Cancel Help Figure 11 2 New File window 3 In the Import Geometry From window displayed select the GEO file named lt Tutorial 4 geo gt located in the Examples folder where the program was installed 4 Click OK The predefined geometry is displayed in the Geometry tab of the View Inout window Fig ure 11 3 This imported geometry contains only the points the layers boundary and the PL lines not the material types and properties They will be imported from an MGeobase database section 11 2 3
309. tion 16 34 into the equation for equi librium of horizontal forces finally yields Equation 16 35 for the safety factor D GEO STABILITY solves this equation in iterative fashion gt Ci yh ui tan Yi b n C yh uj tan Pj bj i l tan a tanp cosa j l tana tany cos y F 5 3R 3Ro ia vihubisina 255a hdj sin as H H le La 3 Fu 3 FH 16 35 Equation 16 35 reduces to Bishop s equations Equation 16 28 if the length L of the com pressed zone is zero and if the radii of the bounding active and passive circles are equal Ay Ro 218 of 264 Deltares 16 4 Spencer Method of slices The Spencer method Spencer 1993 uses the cohesion and constant friction angle as pa rameters These values are obtained in the same way as in the Bishop method with the difference that only the initial c and y are used from a stress table This calculation method is applied in D GEO STABILITY as described below By definition the safety factor is found when the slide plane is in limit state of equilibrium To fulfill this requirement each slice must have equilibrium of moments horizontal and vertical forces The Spencer method satisfies this condition of equilibrium with respect to moments and forces Fast Oj Ne AxjcoS Figure 16 11 Interslice forces according to Spencer method where Qi Slide plane angle Di Slope angle Interslice force angle Pi Internal friction angle along slip surface
310. tistics Layer Properties 116 of 264 Properties Delete Del Undo Ctrl Z Redo Ctri View Preferences Statistics Layer Properties Delete All Loose Lines Delete All Loose Points Figure 7 20 Pop up menu for right hand mouse menu Select mode When this option is clicked the property editor for the selected object is displayed This procedure is performed by first selecting an object by clicking on it with the left hand mouse button Then clicking the right hand mouse button anywhere in the graphic window will display the pop up menu It is possible to use the property editor to quickly adapt the values properties of the selected object Each type of element requires its own properties and therefore its own property editor as shown from Figure 7 22 to Figure 7 25 below This option deletes the element that has been selected see the com ments for the Delete button in section 7 5 2 This option will undo the last change s made to the geometry This option will redo the previous Undo action This option opens the Properties dialog in the Project menu as displayed in It is possible to use this option to view a window displaying all the vital Statistics of the input data Note that in the window construction lines are called free lines This option is a special feature that edits the material properties of lay ers It is possible to click anywhere in a layer and directly choose this option to edit its prope
311. ton Add forbidden lines Click this button to display a window in which it is possible to add modify or delete lines Slip circles are not allowed to cross forbidden lines Add line loads Click this button to display a window in which it is possible to add modify or delete point loads per unit of length Add uniform loads Click this button to display a window in which it is possible to add modify or delete uniform loads per unit of area Edit tree on slope Click this button to display a window in which it is possible to define the position of trees on the slope and the magnitude of wind 7 3 3 Legend At the right side of the View Input window Figure 7 2 the legend belonging to the geometry is shown This legend is present only if the Legend check box in the View Input tab of the Project Properties window is activated see section 4 1 3 x 50 000 Y 11 250 E dit Current object None Figure 7 2 View Input window Geometry tab legend displayed as Layer Numbers 108 of 264 Deltares Graphical Geometry Input In the Geometry tab of the View nput window it is possible to change the type of legend When a soil type box in the legend is right clicked the menu from Figure 7 3 is displayed v Layer Numbers Material Numbers Material Names Figure 7 3 Legend Context menu With this menu there are three ways to display the legend of the layers As Layer Numbers the legend displays one box for each la
312. ts window 1 1 1 a a a 59 Points window ZI 22 gt 60 Confirm window for deleting used points 60 PL lines window 29 WI 61 Phreatic Line window 2 ee o 62 Layers window Boundaries tab 2 2 ee es 62 Layers window Materialstab 63 PL lines per Layer window ccn 64 PL lines and vertical pressure distribution 65 Information window on confirmation of a valid geometry 65 Warning window on confirmation of a valid geometry 65 Slip Circle Definition window Bishop and Fellenius methods 66 Slip Plane Definition window Uplift Van and Uplift Spencer methods 67 Slip Plane Definition window Spencer method 68 Definition of slip planes 2 a a a a 69 Typical situation of generated slip planes 70 Calculation Area Definition window Horizontal Balance method 70 Forbidden Lines window 2 2 2 2 2 25 71 Zone Areas for Safety window 71 Schematization of the zone areas for the Zone Plot model 72 Reference Level for Ratio Cu Pc window 73 Geotextiles window 2 1 6 we a 73 Nail Type Defaults window 2 2 2 2 74 Nails window Geometry tab oaoa oo e 75
313. ty Overview option in the Results menu displays the soil region with a safety fac tor within a certain range according to the results of the various trials that D GEO STABILITY performs when determining the critical slip surface It also displays the regions with a safety value greater and less than the range bounds The default range bounds 1 15 and 1 35 are defined in the Safety Results tab of the Project Properties window section 4 1 3 P Safety Overview ce fn E Safety factor 115 136 X 56 694 Y 9 915 Edit Figure 6 13 Safety Overview window 102 of 264 Deltares 7 Graphical Geometry Input 7 1 7 1 1 This chapter explains how to define the soil layers in a two dimensional cross section by drawing using the shared Deltares Systems Geo tools options for geometry modeling o section 7 1 introduces the basic geometrical elements that can be used o section 7 2 lists the restrictions and assumptions that the program imposes during ge ometry creation o section 7 3 gives an overview of the functionality of the View Input window o section 7 4 describes the creation and section 7 5 describes the manipulation of general graphical geometry using the View Input window Besides graphical input the geometry can also be imported or tabular forms can be used see section 4 3 See the MGeobase manual for a description of special features to create cross section geometry semi automatically from CPT and or boring
314. u de de d d e End of D Geo Stability errorfile Figure 3 7 Error Messages window Manual Select the Manual option from the Help menu to open the User Manual of D GEO STABILITY in PDF format Here help on a specific topic can be found by entering a specific word in the Find field of the PDF reader Deltares Systems Website Select Deltares Systems Website option from the Help menu to visit the Deltares Systems website www deltaressystems com for the latest news Support Use the Support option from the Help menu to open the Support window in which program errors can be registered Refer to section 1 9 for a detailed description of this window About D GEO STABILITY Use the About option from the Help menu to display the About D GEO STABILITY window which provides software information for example the version of the software __ Slope stability software for soft sofl engineering Version 10 1 Build 4 3 e mail supportideltaressystems nl License Unknown Tel 31 88 335 7909 Copyright Deltares 1388 2013 Enabling Delta Life Figure 3 8 About D GEO STABILITY window 28 of 264 Deltares 4 4 1 4 1 1 Input Before the analysis can be started data for the soil structure soil tyoes and loads need to be input Project menu The Project menu can be used to set the model settings The project preferences can be set and it is possible to view the input file Model On the menu bar click Project an
315. u i 5 Sa one plot Cancel Help Figure 21 2 Model window Working with the model The following menu options are associated with the Bishop Random Field Method They deal with inputting stochastic data to obtain factors for the PCRing program Model Factor window All general stochastic data is entered See section 4 2 4 for the input description o Materials window All data related to the soil type is entered See section 4 2 3 5 for the input description External Water Levels window The Bishop probabilistic model determines the conditional probability of failure for a possible maximum of five different external water levels and then apply a Gumbel dis tribution assumption for the water level in order to determine the integrated probability See section 4 6 2 for the input description See section 20 4 5 for background informa tion Note Special for the Bishop probabilistic random field model is that the output from the separate water levels in the pcr file serves as direct input for PCRING Background The Bishop probabilistic model is a strongly modified version of Van Marcke s model Van Mar Cke 1983 Some basic features of the model are discussed in this section For more detailed descriptions refer to Calle 1985 and Calle 1990 Deltares 251 of 264 21 5 1 D GEO STABILITY User Manual Random field model for shear strength Properties of soils in natural deposits may exhibit considerable
316. using the Bishop method and to determine the minimum safety factor To learn to change the existing geometry in the project For this example the following D GEO STABILITY module is needed D GEO STABILITY Standard module Bishop and Fellenius This tutorial is presented in the files Tutorial 1a sti and Tutorial 1b sti Introduction to the case The dike Figure 8 1 has a high water level on the left and a low water level on the right The slope on the right side of the dike is relatively steep There are three different soil layers These circumstances result in the fact that the dike in its current geometry does not meet the required safety criterion A situation like this might occur when river water levels rise It will be seen that placing a berm on the right side of the dike shall result in a more satisfactory safety factor D GEO STABILITY is able to use the geometry water levels and soil layer properties to calculate the minimum safety factor for the dike 17 5m 6 0m 10m 8m 3m 5 0m Figure 8 1 Water retaining dike Tutorial 1 The relevant values of the soil types used in this tutorial are given in Table 8 1 The properties of Berm sand are also given as this soil type will be used to construct the berm later on This berm will help to increase the safety factor Note In general safety factors are described in Design Codes which may vary from country Deltares 119 of 264 8 2 D GEO STABILITY User Manua
317. vises and transfers knowledge on nature and on the environmental engineering of the physical infrastructure wa ter and water defense systems and the supply of construction raw materials including the environmental aspects DWW has sponsored the development of D GEO STABILITY in order to Support a uniform and reliable design of embankments dikes and other geotechnical struc tures For more information on DWW visit www minvenw nl rws dww home On line software Citrix Besides purchased software Deltares Systems tools are available as an on line service The input can be created over the internet Heavy duty calculation servers at Deltares guarantee quick analysis while results are presented on line Users can view and print results as well as locally store project files Once connected clients are charged by the hour For more information please contact the Deltares Systems sales team sales 2deltaressystems nl Deltares 11 of 264 D GEO STABILITY User Manual 12 of 264 Deltares 2 2 1 2 2 Getting Started This Getting Started chapter aims to familiarize the user with the structure and user interface of D GEO STABILITY The Tutorial section which follows uses a selection of case studies to introduce the program s functions Getting Started Starting D Geo Stability To start D GEO STABILITY click Start on the Windows menu bar and then find it under Pro grams or double click an D GEO STABILITY input file that was genera
318. what this means for slope stability on both sides of the dike the strength of the dike layer shall be described by the unsaturated cohesion s The underlying layers will adjust pore pressures more rapidly as they consist of more permeable soils The objective of this exercise is To learn how to assign different shear strength properties to a particular soil layer For this example the following D GEO STABILITY module is needed D GEO STABILITY Standard module Bishop and Fellenius This tutorial is presented in the file Tutorial 2 sti Introduction to the case The same dike geometry as Tutorial 1b is used In this example the water level on the left side of the dike is lowered see Figure 9 1 This might occur when for instance maintenance is needed on the dike The water level is lowered at a considerable place A calculation of the safety factor of the dike is performed when the water level at the left of the dike is at its required level As can be seen in Figure 9 1 the groundwater level in the dike is still quite high Therefore it is now possible to describe the shear strength model for the top layer by its undrained cohesion value Cu which is equal to 6 0 kN m at the top and 8 0 kN m at the bottom of the clay layer 17 5m 6 0m 10m 8m 3m 5 0m Figure 9 1 Dike with lowered water level Tutorial 2 9 2 Project Properties In this tutorial the same file which has been created in the Tutorial 1 is used 1 Cli
319. where axes are required for plots Click Autofit to get D GEO STABILITY to choose the best fit for the page o Print Preview Active Window This option will display a print preview of the current contents of the View Input or Results window o Print Active Window This option prints the current contents of the View Input or Results window Deltares 23 of 264 D GEO STABILITY User Manual 3 2 Tools menu On the menu bar click Tools and then choose Program Options to open the corresponding input window In this window the user can optionally define their own preferences for some of the program s default values 3 2 1 Program Options Program options View Program Options iw Toolbar Iw Status bar Tithe panel Cancel Help Figure 3 2 Program Options window View tab Toolbar or Mark the relevant check box to display the toolbar and or status bar each Status bar time D GEO STABILITY is started Title panel Mark the check box to display the project titles as entered on the den tification tab in the Project Properties window in a panel at the bottom of the View nput window Program options General 24 of 264 Deltares General Program Options Startup with Save on Calculation Mo project le Always Save f Last used project Always Save As New project Use Enter key to f Press the default button v indavws stule Set focus to the nest control DOS stule Cancel Help F
320. window Tutorial 4b See section 4 4 1 3 Slip Plane Definition Spencer for a detailed description of this window 168 of 264 Deltares Tutorial 4 The Spencer Method 11 4 2 Calculation and Results 52 Click Start in the Calculation menu 53 Click OK to perform the calculation 54 Click Stresses in the Hesults menu to open the S ip Plane window P Slip Plane o a ak Edit Materials M R J A Z3 Dike sand erc LL Dike sand 2 Tools LL Stiff clay o j m L1 Peat Clayey sand __ Pleistoceen sand BOG TUU Illa UN y del da Hb Safety 1 30 X 40 620 Y 44 887 E dit Figure 11 19 Slip Plane window with lowest safety factor found by Spencer model Tutorial 4b In the window displayed Figure 11 19 it is possible to see which of the 1024 calculated slip planes resulted in the lowest safety factor For the performed calculation here D GEO STABILITY calculated a minimum safety factor of 1 30 Note There are several possibilities to evaluate more different slip planes One could draw the two defining slip planes further apart or with a different number of points Another is in creasing the number of transversal points It should be noted that a higher number of transver sal points can result in a sharp increase in slip planes to be evaluated This can also have implications for calculation time Note The thrust line of the slip plane is drawn in Figure 11 19 A flaw in Spencer s method
321. wy 1999b a DU defines the ratio between the average standard deviation along separate verticals and the global standard deviation The value is O if the standard deviation ex presses the uncertainty in horizontal direction on the mean value The value is 1 If the standard deviation expresses the uncertainty in horizontal direction on a lo cal value A value of 0 5 is often applicable assuming regular dimensions for a the width of the shearing volume b the horizontal correlation length and c the regions of test sampling yy defines the ratio between the vertical scale of fluctuation correlation length D and the thickness of the layer diayer that is intersected by the slip plane A usual value for D 0 25 m Deltares 241 of 264 20 3 3 20 3 4 20 3 5 D GEO STABILITY User Manual Stress tables D GEO STABILITY determines a standard deviation of the shear strength from stress tables section 4 2 1 by application of the following procedure D GEO STABILITY calculates per layer the average normal stress along the slip plane Onormal ref D GEO STABILITY determines the value of the standard deviation at this reference normal stress from the characteristic and mean value of the shear strength a _ Tref characteristic 4 Far 20 10 U charac During probabilistic analysis D GEO STABILITY will use the shear strength at the reference normal stress 7 e as the random stochastic parameter per layer and scale
322. x on the left click the Add calculation grid button The cursor will change to a hand It is now possible to graphically drop the grid in the calculation domain By left clicking place the grid to the right side of the dike just above its crest The horizontal position can be manually adjusted by left clicking it and dragging it left or right Under the point grid also a set of tangent lines appears Its vertical position can be manually adjusted by left clicking it and dragging it up or down Left click on the grid to select the grid Modify precisely its properties by clicking the right hand mouse and selecting Properties The Slip Circle Definition window appears Fill in the values shown in Figure 8 22 Click OK Slip Circle Definition Grid left nm 43 000 top m 3 000 right m 51 O00 bottom m 6 000 Number E Number la Tangent line Fixed point Y top m 1 500 Use fixed point Y bottom m 4 500 10 000 Number le 10 000 Cancel Help Figure 8 22 Slip Circle Definition window Note The position and coarseness of the calculation grid have an affect on the minimum safety factor in the program also called FMin Firstly when the program finds a minimum value at one of the outer points of the grid it will move the grid This position of the grid will be shifted one grid point distance into the direction of the grid boundary with the minimum safety factor The program will repeat this
323. xit point of the slip circle Aw is the width of the part of the uniform load 7 located within the confines of a slip circle AX is the X coordinate at the middle of the part of the uniform load 7 located within the confines of a slip circle AX is the X coordinate of the line load located within the confines of a slip circle Refer to section 1 8 for the definitions of the other symbols Resisting moments Resisting moment from soil Shear stresses and normal effective stresses act along the slip circle The shear stresses prevent the circular soil mass from slipping The resisting moment Mp so is defined as the moment caused by the shear stresses along the circular arc around the center of the slip circle TU Mr soi Rx Sot X li 16 8 i 1 where 2 is the shear stress along bottom of slice in kN m see Equation 16 9 for Bishop method and Equation 16 10 for Fellenius method Refer to section 1 8 for the definitions of the other symbols Deltares 207 of 264 16 2 2 1 1 16 2 2 1 2 16 2 2 2 D GEO STABILITY User Manual Shear stress Bishop When using the shear strength option c phi or Stress Table together with the Bishop calcula tion method D GEO STABILITY will apply the following formula for the shear stress 7 acting at the bottom of each slice Ci 0 4 X tan ps 7 aL 16 9 1 tano x Fs where Ci is the cohesion at the bottom of slice 2 in KN m Oyi is the vertical effective stress at th
324. y and oy from the user input of x and c x 20 2 20 3 Stochastic shear strength The following subjects are related to stochastic shear strength modeling The definitions presented hereafter are applicable to both a design value analysis and a probabilistic analysis section 20 3 1 Mean value section 20 3 2 Determination of the standard deviation section 20 3 3 Stress tables section 20 3 4 Characteristic value from a normal distribution section 20 3 5 Characteristic value from a lognormal distribution section 20 3 6 Design value 0000202 mean To calculate the mean value of parameter x one can straightforwardly evaluate the following equation 1 n plo a 20 4 pl where n is the number of samples D GEO STABILITY is able determine the mean value from the input of a design value sec tion 20 3 6 For this purpose D GEO STABILITY uses a calculated characteristic value sec tion 20 3 4 section 20 3 5 a partial factor and standard deviation section 20 3 2 associated with the design value The values D GEO STABILITY derives for default standard deviation and partial factors are largely based on Dutch design standards NEN Standard deviation The standard deviation quantifies the uncertainty in a parameter D GEO STABILITY supplies defaults via the variation coefficient V o x 20 5 u x The default values for the coefficient of variation are mainly based on the Dutch NEN standard NEN 1997
325. yer Each layer and there fore each box is displayed in a different standard color Next to each box the layer number and the material name are displayed corresponding to the color and number of the layer in the adjacent Geometry window see Figure 7 2 As Material Numbers the legend displays one box for each material Each material and therefore each box is displayed in a different color which can be changed by the user see below Next to each box the material number and name are displayed corresponding to the color and number of the material in the adjacent Geometry window see Figure 7 4 D View Input ae oC fm Geometry Input Edit m Materials E EX 6 Berm Sand y to E 1 Soft Clay A3 EJ 4 Peat QE E 7 Sand Tool E n X 75 500 Y 0 750 E dit Current object None Figure 7 4 View Input window Geometry tab legend displayed as Material Numbers As Material Names the legend displays one box for each material Each material and therefore each box is displayed in a different color which can be changed by the user see below Next to each box only the material name is displayed corresponding to the color and name of the material in the adjacent Geometry window see Figure 7 5 Deltares 109 of 264 D GEO STABILITY User Manual x 53 500 Y 11 250 Edit Current object None Figure 7 5 View Input window Geometry tab legend displayed as Material Names Unli
326. ying them Recently Teunissen showed us that induced non uniformity which is inherent to localization and fundamental in slip line failure modes still represent space for further improvement The challenge is to incorporate the proper slip mechanism and its relation to local deformations without loosing the elegance of the Fellenius original method Was in earlier times the determination of slope safety a cumbersome handwork of tedious calculations since around the 1960s numerical analysis on the first generation computers led the way to self controlling fast flexible and relatively cheap computer codes such as D GEO STABILITY now suited to run on modern hard and software An experienced supporting team takes care of catching up with relevant scientific progress and new developments such as risk engineering geostatistics and random field approach and the latest computer art of processing and visualization The philosophy after D GEO STABILITY is to keep it user friendly and up to date such that a sufficiently large family of happy users will allow for continuity and further progress Prof dr ir F B J Barends Technical University Delft Civil Engineering department Preface D GEO STABILITY is developed specifically for geotechnical engineers It is a tool used to ana lyze slope stability in two dimensional geometry D GEO STABILITY has proved itself a powerful tool for solving soil stability problems in everyday engineering practice

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