SlopeFE Oasys GEO Suite for Windows
Contents
1. Na FR djMj Mer Mr X sin 6 wj x FS rr i Option1 X 0 sinw tan Option2 X it sing cos6 tanga Option3 X cos 6 wj tanpa The component X represents the nail tension increasing the normal force on the slip surface these are adapted from Figure 18 of BS8006 2 2011 For anchors with prestress BS 8081 applies and an additional restoring moment due to prestress is mi laf ER TYR tan cosle ajl j l where T is the applicable prestress as defined above Circle Centre Critical Slip Surface Figure 1 Oasys Ltd 2014 Essential Background Theory 12 T design tensile capacity of the reinforcing element S the horizontal spacing of reinforcement V design available shear resistance Ra radius of the slip circle 0 angle of the radius from the horizontal 9 angle of the reinforcing element from the horizontal Application of reinforcement forces as surface loads If the Apply as Surface Loads box is ticked currently available for soil nails and ground anchors then the design capacities T and Taj will be resolved into horizontal and vertical load components and applied at the point where the reinforcing element intersects the ground surface The load applied to each slice will be shown in the Point Loads columns of the detailed results output table 4 Getting Started Navigation around the program is done using the commands on the ribbon toolbar and the left navig2. paises e a Ore a A e r a a aO a Aa Gs cuss soa eaaa Eaa artic Er erne 26 23 9 A E a a EA Eae e Eaa aE AE 28 5 34 Material Properties isis aaa AAE kd se AR ek GES Era al EG 29 539 Pe medie E II A a re rss ar 29 5 30 Walerdala ma NN A obs 31 5 37 Stata gt gt ca e e do lo ee 32 9 910 SUP Surface De FIN HO ti 32 53 0 Surface A A 34 5 3 10ReIntorcementanimisa nacida 35 3 9 11Graphical Input aci cua soatueconcoaustanenavanctnmsusrocueusoignasueiraueanvabesasecusansadduessseest alas edites 37 DSAI Kooning DAF Oae e oo 37 5 3 11 2 Groundw dicr boundary conditions wicca canis ce eN ee A 40 Saks MES OOO a A e A E TE EA AA ere 41 6 Analysis and Results 42 O Oasys Ltd 2014 Contents I 6 1 Analysis and Data Checking iii 42 672 Tapular QUID iras 43 021 Summary of Result O AA ENES LES SES ERE SEERE ias 44 622 FulRes lls ius a al E SN EOS 45 6 3 Graphical Outp Ub ccssicsccssneczarcsssscsescascuscacacsiaccotwacaccnesnssssacseacees aesuaroonwecsecnessesezeasroccsneneaeeeusnence 47 0 4 Edit Graphics Sentinel 48 7 List of References 49 TA RETEFENGES ai 49 Index 51 Oasys Ltd 2014 SlopeFE Oasys GEO Suite for Windows 1 Welcome to SlopeFE SlopeFE is a new program which combines finite element steady state seepage analysis with analysis of slope stability by traditional limit equilibrium methods Soil reinforcement can be included The main features are e The ground section
3. List of References References BSI 2010 2011 Code of practice for strengthened reinforced soils and other fills BS 8006 1 2010 and BS 8006 2 2011 Bishop AW 1955 The use of the Slip Circle in the Stability Analysis of Earth Slopes G otechnique Vol 5 No 1 pp 7 17 Janbu N 1957 Earth Pressures and Bearing Capacity Calculations by Generalized Procedure of Slices Proc 4th International Conference Soil Mech Fdn Engng Vol 2 pp 207 212 Nash D 1987 A comparative review of limit equilibrium methods of stability analysis in slope Stability Anderson and Richards eds John Wiley amp Sons Oasys Ltd 2014 List of References so Spencer E 1967 A Method of Analysis of Embankments ensuring Parallel Interslice Forces G otechnique Vol 77 pp 11 26 Whitman R V and Bailey W A 1967 Use of Computers for Slope Stability Analysis International Soil Mech Fdns Div Am Soc Civ Engrs Vol 93 SM4 pp 475 498 Oasys Lid 2014 51 SlopeFE Oasys GEO Suite for Windows Graphical Output 47 A Groundwater 31 Piezometric pressures 31 Groundwater Hydrostatic pressure 31 Analysis menu 42 Analysis Methods Input Data 28 B Interlock 5 Iteration Maximum number of 28 44 Bishop s Methods 5 7 28 Procedure 5 Horizontal Interslice Forces 7 Parallel Inclined Interslice Forces 8 J Variably Inclined Interslice Forces 8 Bitmaps Janbu s Methods 28 42 Adding to titles window 26 Job Number 25 C L
4. Parallel indined Maximum iterations 100 Variably indined Minimum slices 10 Apply Undo The options for full finite element analysis are disabled as SlopeFE is limited to only allow slope stability analysis combined with a steady state groundwater flow calculation At the moment the program also analyses only circular slip surfaces using Bishop s methods Minimum Weight This option will discard slip circles with lower weights this can be useful to exclude small surface slips from the calculations Maximum Number of Iterations All the methods of solution iterate to reach a solution The program defaults to 100 iterations but the user can specify any number Oasys Ltd 2014 29 SlopeFE Oasys GEO Suite for Windows 9 3 4 5 3 5 Minimum Number of Slices The program requires the minimum number of slices for each slip surface to be specified The default value is 10 Soil Nail Analysis These options allow the user to specify the method for calculating the bond stress and restoring moment attributable to soil nails Details of the analysis options are included in the Reinforcement Calculations section Material Properties The Materials command opens this table from either the ribbon or the gateway This table shows the same information as the New Model Wizard material page with the addition of a colour assigned to each material for shading on the graphical input view s ee E Graphics a A renee Material pro
5. 0 0 12 98 11 08 6 140 ba 5532 10 0 0 0 5543 O0 Aldo 94380 5 200 5 548 LL 0 0 0 5543 0 0 8 850 7 352 4 075 4 348 12 0 0 0 5543 OO 44329 9340 55177 5 524 13 2 000 0 3640 Ooi 0 4393 2950 1 846 1 969 The data is printed followed by a summary of the results for all slip circles analysed and a full report of the results for the worst case slip circle with the lowest factor of safety 6 2 1 Summary of Results This output summarises the results for all the slips analysed The following items are tabulated for each slip circle The x and y co ordinates of the Centre of Rotation about which Moment is taken The Radius of the circle for circular slips The Slip Weight The Factor of Safety or Over Design Factor The Disturbing Moment and Restoring Moment of the slip A column for comments provides the following information for circles which were rejected for analysis Comment Suggested action Radius too large Increase lateral extent of ground profile in X direction if required but note that this message will always be shown where the initial radius and increment method is used to define the circles to be analysed Horizontal ground Where the location of the slip surface is entirely within an area of horizontal ground Radius too small Occurs if the circle radius is too small to reach the specified ground surface Center embedded Where the center of the circle is below the level of the top of the slip Oasys Ltd 2014 NOS Sl
6. Circular Slips 4 Loads 34 Results 44 Factor of Safety 44 D M Data Material Properties 29 Checking 42 Input 25 N Date 25 Drained materials 29 Notes 25 E P Errors Bishop s Simplified 7 Data checks 42 44 Phreatic Surface 31 42 Graphical Input 31 37 Hydrostatic pressure 31 Interlock 5 Piezometric levels 31 F Piezometric pressures Adding data 31 Factor of Safety 3 5 28 43 45 R Applied Loads 44 References 49 Results Full 45 Oasys Ltd 2014 Index 52 Results Output 42 43 47 Summary 44 Scale 40 Engineering 40 Set Exact 40 Slices Number of 28 Positioning of 7 Theory of 3 Slip Surface Definition 32 Spencer s Method 8 Strata Graphical Input 37 Tabular Input 32 Surface Loads 34 T Titles Calculation title 25 Window 26 U Undrained materials 29 Units 26 V View menu 47 W Windows Metafile 40 Z Zoom Facility 40 Oasys Lid 2014 53 SlopeFE Oasys GEO Suite for Windows Endnotes 2 after index Oasys Ltd 2014
7. Line Properties dialog which differs slightly according to whether a single line or multiple lines are selected Line Properties multiple selection Mesh generation data Required element size on these lines Post Processing Uptions Movement restraints x Seepage restraints Mone Mo Flow Fixed How 0 Fixed head Phreatic Flow units 0 Piezometric level units 35 Cancel When the mesh is generated the required boundary condition will be applied to nodes generated along the line s with groundwater boundaries specified Note that this dialog also offers the option of setting a required element size on the lines for use in mesh generation To apply to individual nodes either before or after mesh generation select the nodes by clicking the Oasys Lid 2014 oat SlopeFE Oasys GEO Suite for Windows G Nodes button on the Graphics ribbon tab then drawing a selection box or clicking on the nodes Right click and select Seepage restraint from the pop up menu Seepage Restraints Type No flow Fixed flow Outflow m s Fixed head Piezometric level m Phreatic o cae Enter the required information and click OK to apply the boundary conditions 5 3 11 3 Mesh generation To generate nodes and elements for steady state seepage analysis click the ika Mesh button on the Graphics ribbon tab This opens the Mesh Generation dialog in which a default element size can be set This
8. name can be edited by right clicking on the tab and choosing Modify To delete a stratum right click on the tab and choose Delete y SLOPEman sfd Stratum Coordinates x SLOPEman std Graphics OSS e ES N lt a a m PO E O eee Made Ground mee 200000 0 0000 Made Ground ee 10 0000 0 0000 o eee ggap g 0000 eee z oe Pogg ggg eee ER agog pg eee MWH PA O 4 H 14 Stratum 1 A 2 Stratum 2 A 3 Stratum 3 A 4 T If the finite element mesh has already been created editing the stratum data will cause it to be deleted and the basic geometry data will be re created using the new stratum information 5 3 8 Slip Surface Definition The Slip Surfaces command opens this dialog from either the ribbon or the gateway A circular slip surface is defined by the x and y co ordinates of the centre of the circle and the specification of the circle radius The centre of the circle is specified in terms of a single point by x y coordinates or a grid using the x y coordinates of the bottom left corner of the grid and the inclination of the grid about this point positive in the anticlockwise direction Oasys Lid 2014 33 SlopeFE Oasys GEO Suite for Windows 0 0 The extent of the grid is given by specifying the number of columns and the spacing of each grid line in the x and y directions There is an option to let the program extend the grid at the same grid spacing and inclination to find the min
9. of the file To remove a bitmap select Remove 5 3 2 Units The Units dialog is accessible via the Gateway or by choosing Data Units from the program menu It allows the user to specify the units for entering the data and reporting the results of the calculations These choices are stored in and therefore associated with the data file Oasys Lid 2014 Diari Displacement Force Length level Mass Shress SlopeFE Oasys GEO Suite for Windows Conversion factor 1000 per m 0 007 per N 1 perm 1 per kg 0 001 per Pa Time 1 pers Reset Units Default options are the Systeme Internationale SI units KN and m The drop down menus provide alternative units with their respective conversion factors to Newtons and metres Standard sets of units may be set by selecting any of the buttons Sl KN m kip ft kip in Once the correct units have been selected then click OK to continue SI units have been used as the default standard throughout this document Oasys Ltd 2014 Entering Data 28 5 3 3 Specification The Specification command opens this dialog from either the ribbon or the gateway Specification n x Analysis type Finite element displacement stress strain Finite element steady state seepage Slope stability method of slices Mote Analysis method is set to Bishop in this test version Other methods will be added soon Interslice forces Horizontal Minimum weight kN 100
10. of the material The results should therefore be checked for this criterion The interslice force is adjusted separately for both the vertical and horizontal direction by adding the fraction of the residual values from the previous iteration The fraction is determined by the horizontal length of the slip surface represented by that slice The interslice force direction can vary by this method but each slice is in equilibrium at all times as is the slope as a whole Interlock Bishop 1955 pointed out that there are a variety of force distributions which will satisfy the conditions of equilibrium In many cases the assumption of horizontal or parallel inclined interslice forces is reasonable and leads to sensible results Oasys Ltd 2014 Essential Background Theory 6 An important case where errors can occur for horizontal or parallel interslice forces is that of interlock This arises in the case of a deep slip with a low factor of safety where the toe of the slip surface passes through a dense granular material If the deep slip emerges at a steep angle and has a high mobilised angle of friction q where tan q tan d F Then the direction of the resultant force R on the base of the slice may be almost horizontal or even pointing downwards Ground level a Section b Force Diagram In order to satisfy equilibrium of this slice the interslice force X must point upwards This direction is not consisten
11. on the view clicking this button will switch to show only the hydrostatic pore pressure line zero pore pressure at show water table 6 4 Edit Graphics Settings If more than one slip surface is being plotted on the graphical output a legend showing colour intervals corresponding to the plotted range of factors of safety will be shown If there are many analysed circles by default only the 5000 with the lowest factors of safety will be shown To amend this or for more detail within a specific range of factors of safety left click on the plot legend or select Graphics Graphical Output Display settings A dialog box will be shown which allows the minimum and maximum factor of safety to be edited Oasys Lid 2014 NOS SlopeFE Oasys GEO Suite for Windows Edit graphics settings FoS range to show on display Minimum 0 56 Masimum Contour interval on grid of centres 0 125 Maxiniun number of zlip circles to display Cancel Heset 300 The contour interval used in plotting contours of factors of safety is also editable from this dialog Ifa limited range is plotted a note will be added to the graphical output to indicate that not all the available results are being shown see example below The full range can be re displayed by clicking the Reset button on the Edit Graphics Settings dialog Factors of Safety 21 6 152 1 28 1 04 0 80 0 56 NOTE plotted range is a sub set of the results
12. the slip surface with factors on dead and live load applied so w dead load x dead load factor live load x live load factor a is coefficient of interaction between reinforcement and soil relating to the of soil a is coefficient of interaction between reinforcement and soil relating to the c of soil K Is the Rankine active earth pressure coefficient f is partial factor on pull out BS8006 1 3 f is partial factor for structure importance BS8006 1 1 1 lf the bond strength is specified the value B used in the calculations is the user s specified value divided by f xf p n The only partial factor not used at the moment is f sliding along reinforcement which will be added in a later stage of development This would apply if the slip surface is within a certain distance from the reinforcement to reduce strength on slip surface Surcharges are excluded from the pullout calculation by default but can be included by setting the field Use in pullout calc in the Materials table to Yes Oasys Lid 2014 11 SlopeFE Oasys GEO Suite for Windows Calculation of additional restoring moment due to reinforcing elements The additional restoring moment due to the reinforcement is defined as Mar Mar Mpv where Mp7 is the sum of moments due to tension in the nails anchors and Mpy the sum of moments due to shear in soil nails Calculation of shear developed in soil nails is not included so the equation reduces to
13. 5 0 Tangent to stratum Angle of rotation deg 10 about bottom left of the grid Initial radius m Limit radius Centres on grid Features of grid Definition of centres about local ads x direction y direction E Extend grid to find minimum factor of safety number Click Finish to exit the wizard The program will then create data for the finite element analysis for groundwater flow and open the graphical input view to show it O Oasys Ltd 2014 23 SlopeFE Oasys GEO Suite for Windows 5 2 Importing Slope files Selecting Open an existing file on the Startup dialog or the Open command on the application menu see Getting Started opens the File Open dialog LE i EIA Oasys Slopel19 0 Samples i Organize New folder Bs 7 Sr Favorites a prea Desktop de SafeSlopel i I lig Downloads _ de SafeSLOPEman E Recent Places de SafeSLOPEman_ancheors de SafeSLOPEman seepagelines Libraries B Slopel std Select a file to preview e Documents SLOPEman sfd aml Git SLOPEman seepagelines sfd al Music Pictures Ed Videos r 4 IF j File name eepagelines sfd Safe Data Files sfd Sate Data Files std Slope Data Files sld Safe GSA Data Files qwb ee Safe GSA Text Files qwa Safe Data Files sfw Safe DOS Files saf Safe UNIX Files saa All Files This offers various file types in a dropdown list To import an existing Slope file select the S
14. Calculation Completed The groundwater flow analysis is done first and the resulting pore pressures are used as input to the slope stability analysis The Analysis Progress dialog reports how many slip circles have been analysed and also if any have been rejected The reasons for rejecting individual slip circles will be shown on the summary output Once the analysis is complete clicking OK closes the progress dialog Tabular and Graphical output options will then be available in the gateway and on the ribbon Home tab Tabular Output Selecting Tabular Output from the gateway or the ribbon Home tab opens a text view showing the data and results The tabulated output can be highlighted and then copied to the clipboard and pasted into many Windows applications The output can also be directly exported to various text or HTML formats by selecting Export from the Application button menu Slice Strength Parameters Average Slice Forces on base kN m No Pore Weight Pressure c Tan phi KN m2 kN m Normal Shear Shear kN m capacity mobilised 1 0 0 0 5543 0 0 2 275 2 451 1 359 1 450 2 0 0 0 5543 0 0 6 380 6 307 3 496 34 730 Oasys Ltd 2014 Analysis and Results mM 3 0 0 0 5543 0 0 9 652 9 277 5 142 5 487 4 0 0 0 5543 0 0 12 10 11 39 6 314 Gi FIT 5 0 0 0 5543 0 50 134795 12 69 7 035 7 506 6 0 0 0 5543 0 0 14 63 13 24 TESI 7 829 7 0 0 0 5543 0 0 14 76 13 10 Te 299 RES 8 0 0 0 5543 0 0 14 19 12 35 6 844 7 303 9 0 0 0 5543
15. SlopeFE Version 20 0 Oasys Oasys Ltd 13 Fitzroy Street London W1T 4BQ Central Square Forth Street Newcastle Upon Tyne NE1 3PL Telephone 44 0 191 238 7559 Facsimile 44 0 191 238 7555 e mail oasyS arup com Website http www oasys software com Oasys Ltd 2014 SlopeFE Oasys GEO Suite for Windows Oasys Ltd 2014 All rights reserved No parts of this work may be reproduced in any form or by any means graphic electronic or mechanical including photocopying recording taping or information storage and retrieval systems without the written permission of the publisher Products that are referred to in this document may be either trademarks and or registered trademarks of the respective owners The publisher and the author make no claim to these trademarks While every precaution has been taken in the preparation of this document the publisher and the author assume no responsibility for errors or omissions or for damages resulting from the use of information contained in this document or from the use of programs and source code that may accompany it In no event shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or alleged to have been caused directly or indirectly by this document This document has been created to provide a guide for the use of the software It does not provide engineering advice nor is ita substitute for the use of standard
16. al factors Graphical Input Selecting Graphical Input from either the ribbon or the gateway opens the graphical input view The graphical view has geometry data generated from the entered strata coordinates and the problem base level defined in the new model wizard or on importing a previous Slope data file To perform the seepage analysis groundwater boundary conditions should be defined in the graphical view and a finite element mesh generated from the geometry data Data editing is limited in the graphics so as not to invalidate the generated meshing information Stratum points may be moved and lines edited for element size but new lines cannot be added New points may be added so that additional seepage restraints can be specified at the required coordinates Importing DXF data A DXF file can be imported into the graphical input view and used as the basis for stratum coordinates if required Note that DXF data is not saved with the data file unitl selected and added to the model data Right clicking within the graphical view will show a pop up menu from which Import DXF can be selected Erase generated mesh Erase all mesh data Import DAF Import TAT Split crossing lines Highlight gt A File Open dialog is then shown Navigate to the location of the required DXF file select the file and click Open If the coordinates in the DXF file need to be translated enter the required translation coordinates on the dial
17. amp 4 50866 2 1883 194 157 19 157 4 2654 6 5715 0 0 7 3 9559 2 6473 23 153 23 153 5 0280 7 1908 0 0 B 3 1220 3 13956 27 495 27 495 5 4857 7 2027 0 0 9 2 3083 3 6644 32 177 32 177 5 6267 6 6473 0 0 10 1 5158 4_2210 37 191 37 1591 5 4751 5 6417 0 0 11 0 74602 4 8084 42 530 42 530 5 1159 4 3620 0 0 a 12 0 0 5 4258 48 184 48 184 4 6971 3 0253 0 0 13 0 6433 amp 0000 53 4786 53 478 1 3564 0 32847 0 0 14 0 92453 6 2642 55 9244 0 19692 0 34472 0 0 rr Full output comprises the following Method of Analysis Number of iterations Horizontal Acceleration 9 Oasys Ltd 2014 Analysis and Results NOS Location of slip surface x and y co ordinates of the centre of rotation about which moment is taken Radius for circular slips Overall Results Net vertical force Includes net vertical and horizontal Net horizontal force forces to help provide some idea of the possible error in the calculated Slip weight factor of safety Disturbing moment Restoring moment Factor of Safety or Over Design Factor Slip Surface Location Pore water pressure u x and y co ordinates m m OD of Interslice Forces the base of the LEFT side of each slice are used to define the location Vertical Shear T of the slip surface Horizontal Normal E Horizontal Water Pressure E u Slices Strength Parameters Slices are numbered from left to right Cohesion c tan amp degrees Pore Pressure Slice weight Forces on
18. ation panel called the Gateway On first opening the program a welcome screen is shown followed by a start up dialog unless these options have been switched off by the user in the Preferences settings dialog Welcome to SlopeFE Version 20 0 build 18 Getting Started What s New Technical FAQ New model wizard New ribbon layout Opening Slope files Seepage data Graphical output YOU Watch online Technical Support UserVoice Tube tutorials Submit Ideas and Send Feedback E Don t show this again The Welcome screen with options for technical support and obtaining information Oasys Lid 2014 13 SlopeFE Oasys GEO Suite for Windows alopeFE 20 0 build 16 beta Create a new file C Open an existing file Select recent file Show this welcome screen on startup The Start dialog File commands New Open Save Save As etc are also available from the application button menu at the top left corner of the program main window Oasys Ltd 2014 Getting Started 14 Recent Documents 1 DataEntry sfd 2 SimpleSlopelmport sfd 3 SimpleSlopelmport sld 4 SimpleSlope std ad Print Setup The application menu available from the Application button at top left of the ribbon There are three ways to enter basic data into SlopeFE e the New Model Wizard for new files Oasys Lid 2014 15 SlopeFE Oasys GEO Suite for Windows Shear Strength Parameters p 20 2 0 Ab
19. d Surface Loads x i SLOPEman seepagelines std Stratum Coordinates ii a as Diaea Tend Ta emma e Left m Right m Yertical Variable load Unfavourable pull 0 00 0 00 0 00 Horizontal 00 Permanent d mee O a O O i ene E Ye JE E A E SEEGER AREE 1104 _TabTable_ f EM T Loads can be horizontal vertical or inclined O Oasys Ltd 2014 35 SlopeFE Oasys GEO Suite for Windows 9 3 10 Lateral extent of loaded areas x m Right vertical load A Lett Inclined load 144444 4HA Vertical loads are expressed as the vertical force per unit horizontal width of the loaded area For level ground this is equal to the normal stress on the ground surface Vertical loads are positive when they act downwards Horizontal loads are expressed as the horizontal force also per unit horizontal width of the loaded area For level ground this is equal to the shear stress on the ground surface but for steeply inclined surfaces the pressure specified is much greater than the actual pressure acting on the ground Horizontal loads are positive when they act in the direction of increasing x Inclined loads are defined by using a combination of the horizontal and vertical components Concentrated loads in the form of anchors or struts can be modelled by specifying surface loads of high intensity over short lengths of the ground surface Reinforcement The Reinforcement command opens this
20. dialog from either the ribbon or the gateway Four types of reinforcement are available Ground anchors Rock bolts Soil nails Geotextile The data items which are not applicable to each particular type of reinforcement are greyed out when that type is selected from the drop down list Oasys Ltd 2014 Entering Data 36 i SLOPEman seepagelines std Reinforcement Data x h SLOPEman seepagelines sfd Surface Loads F Reinforcement 1 Add reinforcement Name Reinforcement 1 Type Soil Nail Layers Bond Length b Single Multiple Number 3 2 Im O U t Level mi 5 Spacing m 0 7 pcimes EE pacing ln Bond strength Nr Offset from slope surface m ll O Specity 0 io Calculate from effective stress Top nail 5 Bottom nail F Angle from horizontal w 10 Capacity and Spacing Prestress N 0 Out of plane spacing m Ue Grout diameter m 0 6 Tensile capacity N 200 Plate capacity N 100 a ial Maternal partial factors a i hi Select Partial factors z mm H 7 Apply Unda Add Copy Delete Each set of reinforcing elements is given a name which is used to distinguish forces in the reinforcement in the tabular output table Each set is drawn in a different colour on graphical input and output NB If the reinforcement is marked inactive in the Analysis Method dialog it is drawn in grey on the graphical input and omitted from the output becau
21. e of friction at base General Equations The general expression to calculate the average overall factor of safety for a circular slip circle is F ZSR _ Restoring moment HE a q 3 l gg z W Ph Poy Disturbing moment Where S CL N uL tan q and N W P X X_ cos a E E P sin a 1 Note As the factor of safety F is directly related to c and tan 6 it is a factor of safety on material shear strength For models which include soil reinforcement the additional restoring moment contributed by the reinforcement is added to the soil strength restoring moment For details of the method of calculation see Reinforcement Calculations In addition other expressions for equilibrium are as follows For vertical equilibrium Ncos a W P X X S sin a F For horizontal equilibrium N sin a E E P S cos a F n 1 n For full details of notation see Theory of Slices O Oasys Ltd 2014 5 SlopeFE Oasys GEO Suite for Windows 3 1 1 1 3 1 1 2 Method of Iteration Slope uses iteration to reach convergence for each of the Bishop methods as follows Factors of safety For each iteration i Slope calculates a new factor of safety F using the ratio of restoring moment to disturbing moment which is a function of F when the difference between F and F is within the specified tolerance the calculation is complete The factor of safety F is the ratio of restoring moment to di
22. ect the area to be ae viewed The program will automatically scale the new view The original area idii can be restored by clicking on the Unzoom button m F Pan move across a zoomed view Extents re size the view to fit in whole problem area H Show mesh Show mesh Adds the elements to the graphical view Show ruler toggles between showing a ruler at the edges of the view or the i Show ruler view contained within a rectangular border Oasys Ltd 2014 Analysis and Results A x 2 EN Bi m Fy Output options The Parameter dropdown list allows selection from pore Parameter Pore Pressure OreSSure piezometric head nodal flow seepage velocity or hydraulic gradient These parameters can be plotted as line contours filled contours or numbers Slope Graphics a Contour grid Provides a contour plot of the factor of safety for the grid of slip circle centres Show multiple slips toggles between all the circles and only the worst case lt A Show multiple slips _ circle LEA Show slip tooltip Edit slips shown opens a dialog to allow input of a minimum and maximum Ss sis factor of safety to be plotted Other circles will be filtered out and the graphics legend updated Show slip tooltip shows a floating text box with summary details of the currently plotted slip centre radius factor of safety Show water table if the pore pressure contours are shown
23. es out a steady state seepage analysis and the Oasys Lid 2014 SlopeFE Oasys GEO Suite for Windows resulting pore pressures are used in a limit equilibrium slope stability analysis The progress of the analysis including how many slip circles have been analysed or rejected is shown on screen Pause Cancel Groundwater flow analysis progress Iteration lof 0 Cumulative time O Increment O IFAIL ve theration Calculation Completed Warnings Memory used be 2 Slip circle analysis progress 221 slip circles analysed 8 rejected Calculation Completed On completion of analysis the analysis progress dialog closes and the Gateway and ribbon toolbar will be updated to allow access to the tabular and graphical output options Analyse fe Report E Output de Delete results i ig Tabular Output Log files e Analyse Report tab on the ribbon Output options on the Gateway O Oasys Ltd 2014 Getting Started 18 9 Entering Data 5 1 New model wizard Selecting the option to create a new file will open the New Model Wizard If direct data entry is preferred the wizard can be dismissed using the Cancel button The wizard has four pages which are described in the following sections If the Cancel button is pressed before completion of the final page no data will be created 5 1 1 Titles Page The title data entered here are reproduced in the title block at the head of all printed information for
24. imum factor of safety If this option is used the program will extend the grid in any direction if it is found that the centre of the slip surface with the minimum factor of safety is on the edge of the grid This process is repeated until the minimum centre is no longer on the edge of the grid The radius of the slip circle s must be specified as one of the following e The co ordinates of acommon point through which all circles must pass Actual specified location of common point e Defined radii of the circles For this case user can limit the radius value beyond which slips are not generated Slips which do not intersect the ground e g A and B in the diagram will be ignored Oasys Ltd 2014 Entering Data EEN Ay jae Ay deb e E t Nay left limit of section night limit of section e A tangent surface defined as a stratum boundary In this case the circle stays just above the boundary For sloping strata boundaries as shown in the diagram SlopeFE will calculate the shortest radius to the boundary for each centre and take this as the location of the tangent The calculated circle can therefore never cross the strata boundary line p H tangent surface 5 3 9 Surface Loads The Surface Loads command opens this table either from the ribbon or the gateway Surface loads can be added by defining the left and right x coordinates of the loaded area 7 5LOPEman seepagelines sf
25. ing 10 2 2e 006 1e 005 1e 005 0 00 0 00 0 00 1 00 1000 00 1e 006 _ N_TabTable_ A E z Drainage condition Drained means constant pore pressure Undrained means that no volume change will occur and pore pressures are computed Consolidating means that time dependent consolidation is to be computed No water means that there is no water pressure and no flow of water Oasys Ltd 2014 Entering Data so Thus it could be used to model for example an impermeable concrete wall The behaviour is essentially drained i e volume change can occur but unlike other drained zones a no water zone does not interact with consolidation or seepage That is its nodes do not become fixed head nodes forming a drainage boundary Drained undrained and consolidating materials may be used together in the same run Drained elements provide additional fixed heads at their nodes Unit weight of pore The unit weight of pore fluid with depth which is used to calculate pore fluid water pressures from specified data Only in hydrostatic conditions is this yw equal to the weight density of the water yw should be set to zero for layers of soil above the water table which are unable to sustain suction Bulk mod Kw Used for undrained materials Repeated from the general materials table for convenience If Kw is positive it represents the bulk modulus of pore water usually taken to be 2200MN m For Water or Void materials an appro
26. is built up by specifying each layer of material from the surface downwards as a series of x and y coordinates The stratum information is then used to generate a 2D problem domain which is used to create the finite element mesh for steady state seepage analysis e The strength of the materials is represented by specifying cohesion and an angle of shearing resistance Linear variations of cohesion with depth can also be entered Material permeabilities are also required e Fixed head fixed flow or phreatic groundwater boundary conditions should be specified Slopes which are submerged or partially submerged can be analysed e The location of circular slip surfaces is defined using a rectangular grid of centres optionally inclined and then either a number of different radii a common point through which all circles must pass or a tangential surface which the circle almost touches e Any combination of reinforcement consisting of horizontal geotextiles or horizontal or inclined soil nails rock bolts or ground anchors can be specified The restoring moment contributed by the reinforcement is calculated according to BS8006 e External forces can be applied to the ground surface to represent building loads or strut forces in excavations e Analysis first carries out a steady state seepage analysis then uses the resulting pore pressures in the soil mass as input to a method of slices limit equilibrium slope stability analysis e Output inc
27. l This leads to errors in the calculated factors of safety but these are usually small and on the safe side Spencer 1967 2 The method satisfies overall moment equilibrium The limitations of the method have been investigated by Whitman and Bailey 1967 They concluded that the method can occasionally give misleading answers particularly in the case of interlock see Interlock If it is suspected that this may be a problem then the user should select the method of Variably Inclined Interslice Forces Oasys Ltd 2014 Essential Background Theory 8 3 2 2 Bishop s Method Parallel Inclined Interslice Forces This method also known as Spencer s Method is a refinement of Bishop s Simplified Method and satisfies conditions of horizontal vertical and moment equilibrium for the slip as a whole Assumptions 1 The program assumes that all the interslice forces are parallel but not necessarily horizontal i e at a constant inclination throughout the slope Where tan 0 X E X n 1 E n 1 9 angle of resultant of the interslice forces from the horizontal 2 This satisfies the condition of overall horizontal and vertical equilibrium 3 The method also satisfies overall moment equilibrium This method has been assessed by Spencer 1967 He has shown that in most cases the results differ only slightly from those obtained by the simplified method which assumes only horizontal interslice forces The diffe
28. lope Data Files sld option This will allow you to browse to the required file location and select the Slope file to be imported Another dialog describing the data which will be imported and explaining how to complete it for the seepage analysis is then shown The base level of the problem is entered in this dialog to provide a lower level for the geometry data generation If this level is above any of the existing Slope strata the program will calculate it s own base level Oasys Ltd 2014 Entering Data 24 The program will import Slope geometry material and slip surface data and create outline finite element data from it NOTE that water table coordinates MAY be imported as fixed head boundaries if you tick the box below Please check the generated data You may need to add groundwater data and revise material permeabilities as necessary Sate will carry out a seepage analysis and then use the resulting pore pressures for the method of slices analysis Base level of problem m Import water table s The program generates geometry data for mesh generation using the Slope strata coordinates and imports material parameters surface loads slip surface data and reinforcement data Default permeability values are created for all materials If the Import water table s option is ticked the program will also create fixed head boundaries on the geometry data corresponding to the water tables defined in the Slope file O
29. lopeFE Oasys GEO Suite for Windows Calculation of design capacity of reinforcing elements where they cross the slip surface For end anchored elements rockbolts Type B T T S For ground anchors without pre stress or soil nails capacity is the minimum of design pullout force tensile force and stripping force so T min T S BL S P BL S For ground anchors with prestress the applicable prestress cannot exceed this value The input prestress is reduced in proportion to the amount of fixed length outside the slip surface In the output the applicable prestress and any additional capacity are shown separately The applicable prestress per m run of slope is Tj min T T S x LL and the additional capacity is T Ta For geotextiles capacity is the minimum of design tensile force and pullout force so T min T 2L 27 where T is design tensile capacity per m run of slope Tae XT 5_ X fni X fos X fnoo X fn X f where f_ Is the partial factor for creep reduction f 44 IS the partial factor for manufacture f 4 IS the partial factor for extrapolation of test data f 1 4 IS the partial factor for damage f a gt IS the partial factor for environment f is the partial factor for economic ramification of failure f is the partial factor for material strength T is input prestress per anchor S is out of plane spacing B is bond strength force per unit length of anchor nail P is design surface plate capacity L is bo
30. ludes plotting of pore pressures and other water data and display of the analysed slip circles with their factors of safety against failure What s New SlopeFE is a new program which combines finite element steady state seepage analysis with analysis of slope stability by traditional limit equilibrium methods Soil reinforcement can be included The program introduces a new user interface with a ribbon menu and windows which can be docked floated on screen or minimised to the edge of the screen Oasys Ltd 2014 What s New 2 Appheahan Fibbion tabs bation Conte nbbon tat Ribbon category or panel hoger DA y DA fiarai 30 Scale tador 1 The ribbon contains all the commands available in the program organised into tabbed groups The most frequently used commands are on the Home tab Opening some views automatically switches to show the tab most applicable to that view but the tab can always be manually changed by the user Some ribbon tabs are context sensitive and only appear when specific views are open These are highlighted in a different colour at the top of the main screen The Gateway navigation view has links to the various data entry screens and output views lt is docked to the left of the main view but can be moved to another location closed or set to auto hide if required Setting auto hide is done using the push pin symbol at the top of the Gateway It will then mini
31. mise to the side of the main window unless you hover over the minimised view title bar The Gateway can also be closed or re opened using a check box on the Home tab of the ribbon The application button at the top left of the main window takes the place of the File menu Clicking this button opens a menu with access to file operation commands New Open Save etc some view commands Export Print etc and quick access to recently opened files O Oasys Ltd 2014 SlopeFE Oasys GEO Suite for Windows 3 Essential Background Theory 3 1 Method of Slices The following provides details of the basic annotation and sign convention for the method of slices All forces are given as total forces i e including water pressure F Factor of Safety Ph Horizontal component of external loads Pv Vertical component of external loads E Horizontal Interslice Force X Vertical Interslice Force W Total weight of soil ybh N Total normal force acting along slice base R Distance from slice base to moment centre S Shear force acting along slice base h Mean height of slice b Width of slice L Slice base length b cosa Oasys Ltd 2014 Essential Background Theory 4 u Pore pressure at slice base a Slice base angle to horizontal x Horizontal distance of slice from moment centre y Vertical distance of slice surface from moment centre y Unit weight of soil c Cohesion at base b Angl
32. n completion of the import the Graphical Input view will open and show the generated geometry data The example below shows a file with a surface load and a grid of slip circle centres t t Ft te e Ft t t t db e 4 t O Oasys Ltd 2014 25 SlopeFE Oasys GEO Suite for Windows 9 3 9 3 1 You can now continue to add or check and revise the groundwater boundary conditions and generate the finite element mesh for the steady state seepage analysis See Graphical Input for more details Direct data entry and editing Options on the Gateway and commands on the Home category of the ribbon will open tables and dialogs for editing or entering data directly Boundary conditions and some mesh generation data is entered va the Graphical Input view Limited data editing can also be done in the graphics Some data edits in the tables will cause the mesh data to be deleted and re generated The following topics describe each of the data items in detail Titles The Titles dialog allows entry of identification data for each program file Job Number Initials Last Edit Date Pp Model Image 77101 50 jl Job Tite Oasys Manual Example Subtitle Bishops Method Calc Heading Notes Calculation to show the main aspects of a SLOPE induding loads piezometric profiles and a grid of drde ce
33. nded length within the slip circle L is bonded length or length outside the slip circle L is total bonded length The calculation of pullout and stripping forces are mentioned above To calculate them the shear bond strength of the appropriate soil strength model has to be applied to the material the reinforcement is in linear hyperbolic etc B is bond strength force per unit length of anchor nail which can be calculated or specified by the user If calculated the value is based on equation 12 from BS8081 or section 4 3 2 of BS8006 2 Oasys Ltd 2014 Essential Background Theory KO For BS8081 the equation to calculate bond strength is nD o tan Ca Mo xf where OV Y W vertical h is vertical distance between reinforcement and slope surface For BS8006 2 the equation to calculate bond strength is mD o tand c F where 0 0 1 K 2 and K 1 K 2 Shear strength of soil T o a tand Ca Mo x f for drained linear strength model It should be noted that a reduced pullout factor is adopted in this analysis as the factored strength and friction angle are used where f is factor on friction angle 6 is factored soil friction angle tan tan 4 f 4 a c Is factored soil cohesion a c f Yn is weight of soil above the reinforcement behind the slip surface soil unit weight is multiplied by the applicable partial factor w is surcharge on the surface above reinforcement behind
34. ngth materials enter the angle of friction at which a linear Oasys Ltd 2014 Entering Data 20 relationship takes over plus the two constants a and b Slope calculates the material strength using a relationship of t ao_b Then 81 80 abo which is equal to tan 4 at o The associated c is given by c abo 1 b The linear relationship t c o tan takes over at some predetermined q say When o exceeds the stress at which this transition takes place the strength relationship reverts to Mohr Coulomb For drained hyperbolic curve strength materials enter values for c and Do as follows We assume a relationship of t C o tan c o tan Then dr do tand c tan d c on tan 0 c on tan C O tan d is the angle at o O and c value of c when o Both and c are constants c can be calculated from c t o tan 9 For undrained materials enter 1 A single value of undrained shear strength c 2 Alternatively a value of undrained shear strength c which varies linearly with elevation y Where C C K Y y c undrained shear strength at any elevation y C undrained shear strength at a specified elevation y k the rate of increase of shear strength with depth 3 A ratio of c p for normally consolidated soils where p is the effective vertical stress which is calculated by the program at the point on the slip
35. ntres Written by Oasys SlopeFE version 19 0 0 0dew The following fields are available Job Number allows entry of an identifying job number Initials for entry of the users initials Date this field is set by the program at the date the file is saved Job Title allows a single line for entry of the job title Oasys Ltd 2014 Entering Data 26 Subtitle allows a single line of additional job or calculation information Calculation Heading allows a single line for the main calculation heading The titles are reproduced in the title block at the head of all printed information for the calculations The fields should therefore be used to provide as many details as possible to identify the individual calculation runs An additional field for notes has also been included to allow the entry of a detailed description of the calculation This can be reproduced at the start of the data results output by selection of notes using the Print Selection option 5 3 1 1 Titles Window Bitmaps The box to the right of the Titles window can be used to display a picture beside the file titles To add a picture place an image on to the clipboard This must be in a RGB Red Green Blue Bitmap format Select the Paste button to place the image in the box The image is purely for use as a prompt on the screen and can not be copied into the output data Care should be taken not to copy large bitmaps These can dramatically increase the size
36. og which appears Oasys Ltd 2014 Entering Data 38 Translate The graphical input updates to show any lines or polylines imported from the DXF file These are shown in grey and are not yet part of the model data To copy DXF data into the model click the DXF data button DXF Pata on the Select group of the ribbon Click near the centre of any line segment on a line or polyline This will create a stratum for each line or polyline clicked The lines will be re drawn in blue and the Gateway updated to show the new strata added a a SEERE SKS HERE To complete the geometry for mesh generation click the Auto complete button Li Aute complete oy the Generate panel on the ribbon This will create the lines and areas to use as the basis for mesh generation If the DXF polylines do not have the same start and end x coordinates additional lines will be added to the strata so that the left and right boundaries are vertical The program will assume Oasys Lid 2014 39 SlopeFE Oasys GEO Suite for Windows a base level for the problem To set the correct material for each stratum add materials to the Materials table if they have not already been specified and edit the Strata table as required Alternatively click the Areas button on the Select panel of the ribbon and click within each area in turn Right click and choose Set material from the pop up menu The material numbe
37. opeFE Oasys GEO Suite for Windows 6 2 2 Top of circle Centre of circle Weight too small Decrease the minimum slip weight Failed to converge Increase the maximum number of iterations Analysis Error Other calculation errors Check input data Full Results Detailed results are provided for the slip circle with the lowest factor of safety The output provides details of the interslice and base forces in addition to the overall reporting of force and moment equilibrium Fa WORST CASE Centre at 16 000m 24 000m Radius 24 515m Iterations 88 Horiz acceleration g 0 0 Net vertical force kN m 0 15652 Slip weight kN m 125 52 Wet horiz force kN m 0 34472 Disturbing moment kN m 1758 4 Restoring moment kKkNm m 1648 0 Reint BRest Moment kNm m 0 0 Factor of Safety 0 53722 The system of interslice and base forces are in equilibrium When the strengths available at the bases are divided by the computed factor of safety The interslice forces shown in the following table are in equilibrium with the factored strengths of the soil at the bases of slices Slip surface coordinates Pore Pressure Interalice forces EN m Point x m y m L ER T E E u kN m EN m 1 9 3063 0 41623 4 5881 0 0 0 0 0 0 2 8 3801 0 696958 6 7507 6 7507 0 49650 0 67177 0 0 3 7 4659 1 0181 9 3051 9 3051 1 34049 2 1161 0 0 4 6 5645 1 3730 12 227 12 227 2 2986 3 8210 0 0 5 5 6787 1 7633 15 513 15 513 3 3374 5 3961 0 0
38. ove GWL 9 Below GWL i Permeability m s Kc 1 5 y Unit weight of groundwater 10 kN m e import an existing Slope sld file Oasys Ltd 2014 Getting Started 16 js Li Oasys Slopel9 0 Samples Organize New folder FE Desktop a Mm Downloads ll Recent Places Libraries E Documents Em Git al Music Pictures El Videos E My mis al N Name Ly SafeSLOPEman di SafeSLOPEman_anchors Ly SafeSLOPEman 2 Ly SafeSLOPEman 3 di SafeSLOPEman seepagelines sgl test sld kj Slopel sid kJ Slopelbak sld K Slope2 sid Slope2bak sld File name SLOPEman_anchors sld Date modified 24 02 2014 10 24 30 01 2014 14 50 03 03 2014 09 55 03 03 2014 13 03 05 03 2014 10 46 06 02 2014 15 27 15 08 2012 17 19 15 08 2012 17 14 17 08 2012 11 00 17 08 2012 11 00 These methods are described in more detail in the following sections F IT m0 Type File folder File folder File folder File folder File folder Slope Documer Slope Documer Slope Documer Slope Documer Slope Documer The basic data consists of material parameters including permeability stratum coordinates and slip circle definition Surface loads and reinforcement are optional Once the basic data has been defined groundwater boundary conditions must be entered in the graphical input view and the finite element mesh generated and reviewed Selecting Analyse on the ribbon toolbar then carri
39. perties x BEER A A a Shear strength parameters Description pet EN Below Conditi phi OR Cohesi 0 m cu p Colour GWL GWL ERE phi0 OR c0 kN me kN Amem OR b ratio Material 0 00 0 00 Drained linear strength 0 00 0 00 0 00 0 00 0 00 1700 17 00 Drained linear strength 20 00 200 OO ae Sand 18 00 18 00 Drained linear strength 29 00 0 00 bd RER Clay i 21 00 21 00 Undrained ney 75 00 5 00 0 50 0 00 ae 4 _ SandLens 18 00 18 00 Drained linear strength 30 00 0 00 dl lc For details of the parameters see the Materials Page topic Permeabilities The Permeabilities command opens this table either from the ribbon or the gateway Permeability information is required for every material and will be automatically created with the values specified in the New Model Wizard or with default values if a Slope file has been imported i TE BE SEE Permeabilities x Ze SLOPEman EA Graphics lie Se a HEE iitim v D ti E NCH wt of P biliti en LEE am y escription men pe fluid Silica ME A k aan ae y O A kN Ze O AO E u B C B CT kN 7m Y L Material No water 2 2e 006 7 1 00 1000 i 1006 7 1 Made Ground Consolidating 10 2 2e 006 le 005 1e 005 0 Do 0 00 0 Do 1 00 1000 00 1e 006 2 Sand 10 22e 006 1e 005 e005 0 00 0 00 0 00 1 00 1000 00 1e 006 Clay Consolidating 10 2 2e 006 1e 005 1e 005 0 00 0 00 0 00 1 00 1000 00 1e 006 Sand Lens Consolidat
40. priate value must always be quoted Permeabilities Orthogonal principal permeabilities k1 k2 k1 horizontal if inclination is zero k2 permeability at right angles to k1 Inclination Inclination of the first principal permeability measured anticlockwise from the x axis specified in degrees Level yO Set these values if the permeability varies with depth within the material Beta yO is the reference level at which k1 and k2 have been defined and Beta describes the relationship between that and permeability at other depths B dk dy K yo where K y0 is K at yo Desensitising factor F This must be set to 1 0 for all materials for which an accurate consolidation analysis is required However it will sometimes be the case that the problem involves low cv materials for which accurate consolidation is required and high cv materials which provide boundary conditions to the others and for which some error in pore pressure could be tolerated In this case it is desirable that the time steps are suited to the low permeability materials and the desensitising factor is used to keep the high permeability materials in a stable state In effect for each iteration the coefficient of consolidation of the high cv materials is decreased by this factor however the overall effect is made less severe as iterations proceed within each time increment Users must inspect the results for materials with values of F greater than 1 0 and sati
41. r can then be entered in the Area Properties dialog Area Ae Void Material 3 Lines on boundary 11 19 13 121678910 Oasys Ltd 2014 Entering Data 40 5 3 11 2 Groundwater boundary conditions Groundwater boundary conditions are required for the steady state seepage analysis which calculates pore pressures within the soil mass Boundary conditions can be one of four types no flow fixed head fixed flow or phreatic Seepage boundary conditions can be applied to mesh generation lines or to individual nodes Fora fixed head node the piezometric water level at the node must be entered For a fixed flow node the flow rate must be entered units m3 s m Phreatic nodes are defined as those at which water may leave the mesh and the water pressure at these nodes will be maintained at atmospheric pressure No flow nodes allow no net flow of water into or out of the finite element mesh Internal nodes are taken to be no flow nodes by default and these do not need to be specified Nodes at an interface with drained elements are normally treated as fixed head nodes in the computations if this is not required they may be declared here to be no flow To apply to mesh generation lines before generating the mesh select the lines by clicking the TW Lines button on the Graphics ribbon tab then drawing a selection box around the required line s centres Right click and select Modify from the pop up menu This will open the
42. references The user is deemed to be conversant with standard engineering terms and codes of practice Itis the users responsibility to validate the program for the proposed design use and to select suitable input data Printed July 2014 SlopeFE Oasys GEO Suite for Windows Table of Contents 1 Welcome to SlopeFE 1 2 What s New 1 3 Essential Background Theory 3 So Metodo SIICC Ss 3 ST General EQUATONS a eaaa 4 3 1 1 1 Method eras e a e e e a E DRS ES 5 3 1 1 2 E 6 en OA ee ne en On ee A ee ee ee AR ET 5 Sco POSIMOMING Ol SIG CS is ERNE ai 7 3 2 Bishop S MONOS ta 7 3 2 1 Bishop s Simplified Method Horizontal Interslice Forces oomccccoocnccnnsnccnnnaccnnnnanonnnnncnnnnanonnnnanonnnane rana rr nnnannnns 7 3 2 2 Bishop s Method Parallel Inclined Interslice Force S ccomcmccooncncconnanccnnnnconanaconnnnanonnnancrnnna ronca n nr nana rnna rr rnnaannns 8 3 2 3 Bishop s Method Variably Inclined Interslice Force S mccomonmnnncnnncnnncsnnnnsnnennconnnnnnne narran nenes ne nseries 8 3 3 Reinforcement Calculations at ae 8 4 Getting Started 12 5 Entering Data 18 51 New mod rwiz rd sidra EE E ENES 18 Sala IGS Page da A caus 18 SA Materials Page corinae AA A AE 19 5 1 3 Stratum Definition Page ocrni a aaa RENE 20 5 1 4 Slip Surface Definition Page sa E Aa aa e E 22 5 2 Importing Slope file S arrn da 23 5 3 DIFECL Gata entry and Cali oia iia 25 TAS A a a aa 25 DSL TT Mes VWWINGOW II Pc AA a 26 BSUS
43. rences between the two methods increase with slope angle For steep slopes Spencer s method is more accurate and is therefore recommended This method can have problems of interlock see Interlock If it is suspected that this may be a problem the method of variably inclined interslice forces should be used 3 2 3 Bishop s Method Variably Inclined Interslice Forces This method is a further refinement of Bishop s method designed to over come the problems of interlock Assumption e In this method the program calculates the interslice forces to maintain horizontal and vertical equilibrium of each slice The inclinations of the interslice forces are then varied in each iteration until overall horizontal vertical and moment equilibrium is also achieved 3 3 Reinforcement Calculations lf reinforcement is specified and active the forces in the reinforcement are calculated and can be either specified as contributing additional restoring moment hence increasing the factor of safety or as surface loads where the surface load applied equals the capacity of the reinforcement derived for the current slip surface lf the reinforcement is used to contribute additional restoring moment the soil restoring moment is calculated as usual but with any partial factors taken into account then divided by the moment correction factor The reinforcement restoring moment is then added and the factor of safety calculated Oasys Lid 2014 9 S
44. se it has no effect on the results Geometry The uppermost level number of layers and horizontal spacing are entered The length of the top and bottom layers of reinforcement are entered The lengths of intermediate layers are interpolated between these two values The angle from horizontal is entered except for geotextiles which are always assumed to be horizontal Capacity Out of plane spacing tensile capacity and plate capacity if applicable are entered Plate capacity must be at least 50 of tensile capacity The tensile capacity should represent the allowable capacity if BS8081 is used or ultimate capacity if EC3 is used Bond details and prestress Bond length can be entered for ground anchors and rock bolts Type B Soil nails are assumed to be 100 bonded along their length Oasys Lid 2014 SlopeFE Oasys GEO Suite for Windows 5 3 11 5 3 11 1 Bond strength can be specified or calculated from effective stress Prestress can be entered for ground anchors and can not exceed the tensile capacity Material partial factors Click the Select button to set material partial factors for each set of reinforcing elements This is optional all partial factors will be set to 1 0 if no selection is made User defined sets of partial factors can be added or edited by selecting Partial Factors from the View menu See Reinforcement Calculations for details of the calculations used and the application of method and material parti
45. sfy themselves that they are appropriate for the problem Min pwp Minimum pore water pressure attainable by the material This is the pressure at which the material becomes unsaturated it will generally be zero or negative representing suction For unlimited suction leave blank Oasys Lid 2014 31 SlopeFE Oasys GEO Suite for Windows Permeability factor If the pore pressure in the element tends to fall even lower than that specified above it will be held at the specified minimum and the permeability of the element will also be reduced by this user specified factor This represents conditions in a non saturated zone In simple cases the factor should be set very low the default is 10E 6 meaning that the permeability of the unsaturated material is one millionth of the saturated value Other values could be used given a proper understanding of unsaturated flow 5 3 6 Water data This command opens a read only view of the water boundary conditions These will usually have been assigned to lines or nodes in the Graphical Input view _SLOPEman BEEN a O Restraints x sat Restraint Outflow level type m oe s m Oasys Ltd 2014 Entering Data 32 5 3 7 Strata The Strata command opens this table either from the ribbon or the gateway The table shows a page for each stratum entered with the x and y coordinates and the material type in the first record only The stratum
46. size will be overridden if other sizes have been set for individual lines or nodes Mesh Generation Background mesh General element size 1 4 This will be overridden where a specific size has been set for a nade Fost processing Renumber during mesh generation Advanced It is recommended to use the default option to renumber during mesh generation Click OK to generate the mesh Some numbering statistics will be reported on completion of mesh generation Oasys Ltd 2014 Entering Data a2 Generation Statistics The fae Sho button can be used to view the mesh ee 4 4 4 H tt ttt e ee ee ee 4 4 4 4 4 4 od bee ee 4 4 e ee ee eH tee ee He 4 ee ee eet ote ae Se Ee ee EE PE HE EER EHR BEEEE RARER EET os SPEEA gt BEE EEE 6 Analysis and Results 6 1 Analysis and Data Checking To run the seepage and slope stability analysis click the Analyse button on the ribbon Home tab Prior to analysis the program carries out some data checks and will report for example if groundwater boundary conditions are not specified Oasys Lid 2014 NOS SlopeFE Oasys GEO Suite for Windows 6 2 Pause Cancel Groundwater flow analysis progress Iteration lof Cumulative time 0 Increment O IFAIL ve theration Calculation Completed Warnings Memory used be 2 Slip circle analysis progress 221 slip circles analysed 8 rejected
47. sturbing moment However this ratio is itself a function of F except in the Swedish circle method so an iterative solution is necessary Horizontal interslice forces 1 Slope starts at slice 1 Note Slices are numbered from left to right and by maintaining vertical equilibrium it calculates the resultant horizontal force 2 The program then uses this as the interslice force with slice 2 The process continues until the last slice which ends up with a resultant horizontal force In this method each slice and the slope as a whole is in vertical equilibrium with zero vertical interslice forces Horizontal equilibrium is not achieved within each slice or the slope as a whole Therefore the only force check within each slice is for vertical equilibrium Constant inclined interslice forces In this method Slope varies the ratio which is constant between the vertical and horizontal interslice forces until the resultant of each is reduced to zero For this method each slice is not in equilibrium only the slope as a whole In the calculation equilibrium is effectively maintained for each slice in the direction normal to the interslice forces Variably inclined interslice forces The variably inclined method is superior as it Keeps every slice in horizontal and vertical equilibrium at all times However it can exceed the soil strength along the slice interface as it does not check the vertical interslice forces against the shear strength
48. surface for each slice 4 A combination of 2 and 3 If both are selected then the higher value of strength is used Once all required data has been entered click the Next button to move to the stratum definition page 5 1 3 Stratum Definition Page This page allows specification of stratum coordinates and their materials and also the base level of the problem An empty Stratum 1 is created on moving to this page for the first time Coordinates of the stratum should be added in increasing x coordinate order To add more strata expand the dropdown box next to Name and select lt New gt This creates a new stratum with a default name Continue to add strata and their coordinates until they are all defined Oasys Lid 2014 21 SlopeFE Oasys GEO Suite for Windows Mew Model Wizard Stratum Definition Stratum Coordinates Level of base of problem m Enter the base level of the problem this will be used in mesh generation later and click Next to move to the Slip Surface Definition page O Oasys Ltd 2014 Entering Data 22 5 1 4 Slip Surface Definition Page The final page of the new model wizard allows setting of options for the slip circles For more details see the main data entry Slip Surface Definition Cirdle centre specification Circle radius specification O Single Grid Common point Coordinates of bottom left if a grid specified Defined radii x Im 40 Coordinates x m 0 y Im
49. t with the assumption of either horizontal or parallel inclined interslice forces Varlably inclined forces act in the correct direction to take Interlock into account Horizontal Interslice Forces a Parallel Interslice Forces A Variable Inclined Interslice Forces In such cases the method of variably inclined interslice forces should be used Oasys Lid 2014 SlopeFE Oasys GEO Suite for Windows 3 1 1 3 3 2 3 2 1 Note Slope does not provide a warning when this problem may occur Positioning of Slices Slope divides each slip mass into a number of slices The resulting slice boundaries are located at the following points at the left and right hand extent of the slip surface at the change in gradient of a stratum at each slip surface stratum intersection at each slip surface phreatic surface intersection at the mid point of a slice whose width is greater than the average slice width given by Xight X Minimum number of slices Bishop s Methods Bishop s methods Bishop AW 1955 are applicable to circular slip surfaces Three methods of solution are available These are Horizontal Interslice Forces Parallel Interslice Forces Variably Inclined Interslice Forces Bishop s Simplified Method Horizontal Interslice Forces Assumptions 1 The interslice shear forces are assumed to sum to zero This satisfies vertical equilibrium but not horizontal equilibrium where YA i Ku
50. the base Normal N Shear S General Slice Information Surface Loads vertical and horizontal Water pressure on ground surface Vertical and horizontal Oasys Lid 2014 SlopeFE Oasys GEO Suite for Windows 6 3 Graphical Output The ribbon command or the Gateway item Graphical output open the graphical output view A new ribbon tab specifically for Slope Graphics is also added to the ribbon when this view is open The program defaults to show all slip circles or by default a maximum of 5000 slip circles coloured in accordance with their factor of safety To change the currently plotted circle when a grid of centres has been analysed move the cursor into the grid and right click on the required centre The circle with the lowest factor of safety for that centre will be plotted First Re TS A 0 46000400090 de 66 gt t FR E FUR 9601400940000 L E E E O ee7ee O 6001414094009 C E 090 EEEE E E r ay oe to SLOPEman seepagelines Event 1 Run 1 Increment 1 13 00 12 03 14 Scale x 1 244 y 1 244 A number of other output options and commands are available on the Graphics and Slope Graphics ribbon tabs Graphics tab A Zoom Extents Zoom Select an area to zoom in to by using the mouse to click on a point on the drawing and then dragging the box outwards to sel
51. the calculations An additional field for notes has also been included to allow the entry of a detailed description of the calculation This can be reproduced at the start of the tabular output if required Selection of units for data display can also be done from here More detail on the options available is in the main Units topic Oasys Lid 2014 19 SlopeFE Oasys GEO Suite for Windows 12345 11 Slope stability example Subtitle Calc Heading Notes Click the Next button to move to the materials page Materials Page This page allows specification of material parameters Some default values for the first material are initially shown To add more materials expand the dropdown box next to Material Name and select lt New gt This creates a new material with a default name which can be edited to have the required parameters Continue to add materials until they are all defined The following should be entered for each material e A description of the stratum e The bulk unit weight kN m of the material above and below the ground water table Shear Strength Parameters e The condition of the material e undrained drained with linear strength or drained with strength calculated using a power or hyperbolic function Choose the required option from the drop down list For drained linear strength materials enter the angle of friction d deg and a value for drained cohesion c For drained power curve stre
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