TOCHNOG PROFESSIONAL Tutorial manual Version 23
Contents
1. start_define upper_edge_load geometry line counter_a end_define lower_edge 0 0 0 0 12 0 0 0 eps_geometry right_edge 12 0 0 0 12 0 8 0 eps_geometry left_edge 0 0 0 0 0 0 8 0 eps_geometry upper_edge_load 4 0 8 0 8 0 8 0 eps_geometry The edges lower_edge right_edge and left_edge will be used to impose boundary conditions The upper_edge_load will be used to impose the top load 5 1 5 Data part excavation geometries start_define excavation_0 geometry_quadrilateral counter_a end_define start_define excavation_1 geometry_quadrilateral counter_a end define start_define excavation_2 geometry_quadrilateral counter_a end_define start_define excavation_3 geometry_quadrilateral counter_a end_define start_define excavation_4 geometry_quadrilateral counter_a end_define excavation_ 0 0 0 7 0 3 0 7 0 0 0 8 0 3 0 8 0 eps_geometry excavation_1 0 0 6 25 3 0 6 25 0 0 8 0 3 0 8 0 eps_geometry excavation_2 0 0 5 0 3 0 5 0 0 0 8 0 3 0 8 0 eps_geometry excavation_3 0 0 4 0 3 0 4 0 0 0 8 0 3 0 8 0 eps_geometry excavation 4 0 0 3 0 3 0 3 0 0 0 8 0 3 0 8 0 eps_geometry Here five geometry_quadrilateral are defined which will be used for the excavations Please pay close attention how the coordinates of the quadrilaterals are specified for excavation_0 the first coordinate is 0 0 7 0 the second coordinate is 3 0 7 0 the third coordinate is 0 0 8 0 and finally the fourth coordinate is 3 0 8 0 If you would specify these coordinates in another2. 34 ir A de asd Bia er dad de pi E 35 5 3 Output results 44 neema aa daa ee a a Bomb dE a 35 6 Tutorial 4 excavation with sheet pile isoparametric and interface elements 38 62 Inpu tfile isla ro dala a ee ao 4 Oh aoe Ba Ak ee he BR ewe BG 38 6 1 1 Initialization part 2 24 4 ee be a 38 poe bbe a dee ede e 38 6 1 3 Data part geometries 39 ge a 39 6 1 5 Data part generate mesh with Tochnog 39 6 1 6 Data part post processing and printing 40 bab ed 4 Deed date ea a Bb eee a Ge 41 Lhe wien RU Be AE OS Ree AA IS NA eae 42 dus a a ad 42 1 Conditions All conditions from the Tochnog Order form apply See our internet page for the latest order form 2 Basic information The tutorials in this manual describe calculations in decreasing detail The first tutorial discusses many aspects whereas the following tutorials discuss less aspects You can find these tutorials on your distribution in the directory tochnog test tutorial Mesh preparation and post processing is done with Gid 7 6 0b under Linux Gid is copyrighted by CIMNE see http www gidhome com It is advised to learn Gid first The advanced user under Linux can also find examples on how specific input commands are used by grepping in the tochnog test input files in the tochnog test other directory e g grep control_timestep dat 3 Tutorial 1 slope safety factor analysis This tutorial i
3. 349065 in radians so 20 degrees and the cohesion c 10 044 group_type 1 materi group_materi_memory 1 total_linear group_materi_density 1 2 0 group_materi_elasti_young 1 1 e5 group_materi_elasti_poisson 1 0 3 group_materi_plasti_tension_direct 1 10 0 group_materi_plasti_mohr_coul_direct 1 phi c 0 0 When we made the mesh with GID all elements were assigned to group 1 Here we define the material properties of group 1 The group_type is set to materi which means that material strains stresses etc will be solved With group_materi_memory set to total_linear you specify a classical geometrically linear small deformations approximation for the soil this is suf ficient for almost all typical calculations The soil density is set to 2 1000 59 in the data record group materi density The Young s modulus and Poisson s ratio are 1 6544 and 0 3 as set mr in the records group_materi_elasti_young and group_materi_elasti_poisson respectively For shear failure the Mohr Coulomb yield surface is used the record group_materi_plasti_mohr_coul_direct specifies the friction angle the cohesion c and zero dilatancy To include tension failure limitation of tensile stress in soils you explicitely need to include group_materi_plasti_tension_direct in the input file here the maximum tensile stress is set to 10 044 change_dataitem 10 group_materi_plasti mohr_coul_ direct 1 0 use change_dataitem_time 10 0 0 tanphi 1 0 tanphi 2 0 0 1
4. 900 3 01 2 0 3 01 8 0 control_print_dof_line_n 900 10 control_print_dof_line 910 yes control_print_dof_line_coordinates 910 2 99 2 0 2 99 8 0 control_print_dof_line_n 910 10 34 To obtain X Y graphs of the pressure of the soil on the left side and right side of the sheet pile the control_print_dof_line_ data records are used With index 900 printing of all solution fields is demanded for the line starting at point x 3 01 y 2 0 and ending at a 3 01 y 8 0 so that is a line just to the right of the sheet pile The solution fields are printed at 10 points along that line The fields are printed in text files by example velx 900 sigxx 900 etc Similar with index 910 the solution fields will be printed along a line just to the left side of the sheet pile 5 2 Run calculation On Linux open a window and type tochnog tutorial _3 On Microsoft Windows open a DOS command prompt and type tochnog exe tutorial 3 See also tutorial 1 for the type of files that you can find after the calculation 5 3 Output results Wane deed AAA N 2 CA y Figure 17 Material displacement mesh View results Display Vectors materi displacement In the post processor of Gid look at the displacements at the end of the calculation Especially notice that at sheet pile you see two displacements vectors one is a vector of the sheet pile dis placement and the other is the vector of the soil displacement near the sh
5. been used here 4 2 5 Data part groundwater groundflow_density rho groundflow_seepage_geometry 0 left_edge The groundwater density p as specified in groundflow_density is 1 010 On the total left edge there is air so later we will prescribe in the boundary conditions that the pore pressure is zero at the left edge However we also need to be sure that the flux of water can only be directed outward the dam at the left edge and water cannot enter the dam at the left edge This is accomplished be using a seepage condition as specified in groundflow_seepage_geometry with such condition Tochnog will take care that water flux can only be outward and not inward 4 2 6 Data part boundary conditions on edges bounda_dof 0 right_wet_edge pres bounda time 0 200 0 bounda_dof 1 left_edge total_pressure bounda_time 1 0 0 The bounda_dof records are used to prescribe conditions for the water pressures On the part of the right edge below the water level a hydraulic head h of 200 0 is prescribed the word pres means hydraulic head You can understand that is OK by looking at the equation for the total pressure pore pressure Ptotal pgy With density p 1 0 gravity g 10 0 we find at y 0 0 that the pore pressure is 200 0 and at y 20 0 that the pore pressure is 0 0 19 On the total left edge we prescribe a zero pore pressure On the bottom edge we don t allow for any groundflow flux In Tochnog a zero norm
6. calculate the total pressure pore pressure remember that primarily the hydraulic head is calculated in a groundflow analysis so that the total pressure is only available as extra post processing option The post_node records are a convenient method to determine in structural calculations forces on prescribed displacement edges or here in a groundflow calculation the groundwater flux to the environment Using post_node 0 node_rhside sum left_edge as shown here causes the right hand side to be summed over all nodes which are located in the geometry left_edge The result will be placed in the record post_node_result which can be printed during the calculation or found in the database after the calculation You find in post_node_result the required flux at the position consistent with the initialized groundwater pressure variable Look in dof_label after the calculation there you see that the first variable is the hydraulic head pres and thus you find the groundwater flux also at the first position in the post_node_result record 20 4 2 9 Data part apply linear time steps control _timestep 10 1 1 control_groundflow_nonsaturated_apply 10 no control_groundflow_seepage_apply 10 no control_print 10 time_current post_node_rhside_ratio This nonsaturated dam calculation is highly nonlinear because of the group_groundflow_nonsaturated_vang and the groundflow_seepage_geometry records In order to get a solution a trick is commonly appl
7. cohesion and friction angle causes is evi ircular segment slides away It ity clearly shows how a c il that the Mohr Coulomb shear fa th instab The velocity profile at lon W t i ilure cond tability 1s 1ns 16 4 Tutorial 2 non saturated dam with seepage edge This tutorial shows how to perform a non saturated groundflow analysis in a dam Figure 7 shows the dam 55 65 45 lt Le gt gt allie 30 20 165 I gt Figure 7 Dam At the lower part of the right edge a water level of 20m is present by example because of a lake The lower edge of the dam does not allow for inward or outward flow of ground water it is non permeable The left edge is a seepage edge it only allows for outward water flow and not for inward water flow 4 1 Mesh generation with Gid The mesh generation in Gid is very similar to tutorial 1 so it is not repeated here We just remark that the element size as required in the Gid Mesh Generate dialog should be set to 1 0 to get a reasonably fine mesh Figure 8 Nurbs surface of dam F igure 8 shows the Nurbs surface Figure 9 shows the mesh 4 2 Input file 4 2 1 Initialization part echo yes number_of_space_dimensions 2 groundflow_pressure groundflow_saturation 17 Figure 9 Mesh of dam groundflow_velocity end _initia The groundflow_pressure takes care that the hydraulic head field becomes available over
8. contain the element number the element name here tria3 and finally records contain for each node the coordinates fields need to be solved The data part specifies elements nodes boundary conditions etc Write file with tochnog elements nodes and element groups Save everything to the directory mesh The input file always contains two parts The Calculate Calculate 3 2 Input file File Save As Save g 3 2 1 Initialization part echo yes number_of space _dimensions 2 materi_velocity materi_displacement materi stress materi_strain_plasti end _initia The first line echo yes tells Tochnog that the input should be echoed when it is read This is convenient in locating errors in your input file you can see up to which line the input file is read before the error occurs Use echo no if you don t want to echo the input file The number_of_space_dimensions 2 specifies that the dimensionality of the calculation is 2D plane strain plane stress or axi symmetric Also 1 and 3 are available in Tochnog thus 1D and 3D The materi velocity together with the materi_displacement takes care that the velocity and displacement fields are present for solution Since this is a 2D calculation only the x and y components are present in the calculation Initialization of the stress field is done with materi stress Please realism that all the 9 com ponents o of the 3D stress matrix are present in the calculation since
9. e tutorial_1 dbs This is the database after the calculation It contains all information from the calculation input data results etc e tutorial_1_flavia msh and tutorial_1_flavia res Post processing files which can be opened with Gid e tochnog log Log file from Tochnog which lists the calculations that have been run e post_point_dof_10_disy his History file with time versus y displacement for the post_point 10 3 4 Output results 3 4 1 Determine safety factor You will see that at time 1 36 the friction angle and cohesion have become such low that the slope becomes unstable At that time the cohesion has decreased from 10 024 to 1 0 36 x 10 0 6 4 The safety factor thus is as 1 56 3 4 2 Plot displacement history in Gnuplot A history plot of the vertical displacement of the post_point in the file post_point_dof_10_disy his shows what is happening when the cohesion and friction angle are lowered in time between 1 0 and 2 0 Here we use Gnuplot as plotting program but since the file post_point_dof_10_disy his 14 is a simple ASCII text file you can use any program of your preference for plotting With Gnuplot do the following for getting a postscript result of the displacement history gnuplot p post_point_dof 10_disy his with lines set term postscript set output post_point_dof_10_disy ps replot 0 1 T T T 3 post_point_dof_10_disy his 0 002 Oe 0
10. e20 0 0 change_dataitem_time_method 10 tangent change_dataitem 20 group_materi_plasti mohr_coul direct 1 1 use 11 change _dataitem_time 20 0 0 c 1 0 c 2 0 0 0 1 e20 0 0 The change_dataitem and change _dataitem_time records take care that the friction angle and cohesion are lowered in the calculation so that we find the minimum friction angle and cohesion for stability The ratio of the start values and the minimum values will define the safety factor The change _data tem 10 record specifies for the group_materi_plasti_mohr_coul_ direct record with index 1 so group 1 and number 0 With number 0 the first value in the group_materi_plasti mohr_cc is meant thus the friction angle The diagram in change data tem time 10 specifies that at time 0 0 the friction angle is the predefined word phi thus 0 349065 at time 1 0 it is again the predefined word phi at time 2 0 it is 0 0 and at time 1 0e20 it is 0 0 Between the specified time points the value will be linearly interpolated The use specifies that the given values should actually be used as opposed to other options see the users manual Similarly the cohesion is varied in time with change _dataitem 20 and change _dataitem_time 20 3 2 6 Data part prepare post processing post_point 10 20 0 15 0 With post_point 10 a point in the domain is defined at which Tochnog will monitor during the cal culation solution fields The solution field at the point will be place
11. in fact at a geometry_point see the previous definition of beam_point This will only work correctly if at that point in space there really is a finite elements and their nodes If on that point in space there is no node no condition will be applied at all This remark holds for all kind of data where you use geometries e g loads on edges post processing on geometries etc in the end such data will only be applied on finite element nodes so these nodes should be located on the correct locations 5 1 8 Data part distributed force load on top force_edge 0 0 0 10 0 force_edge_geometry 0 upper_edge_load force edge time 0 3 0 0 0 4 0 1 0 1 e8 1 0 28 The force_edge 0 records specifies a distributed edge force of 10 0 4 in y direction so in fact in negative y direction This force will be applied to the element edges which are part of the upper_edge_load as specified in force_edge_geometry 0 Since this force is only applied in the experiment after time 3 0 we need the force edge time 0 data records which contains a time versus multiplication factor diagram Using this force edge time diagram before time 3 0 the load is 0 0 between time 3 0 and time 4 0 the load increases from 0 0 to 10 0 and it remains 10 0 after time 4 0 5 1 9 Data part gravity force_gravity 0 9 81 The gravity acceleration is BEE and is present directly from the start of the calculation We do this because later we will directly set initia
12. order 26 you get false results for the excavations 5 1 6 Data part material properties start_define soil0_group 0 end define group_type soil0_group materi groundflow group_materi_memory soil0_group total_linear group_materi_density_groundflow soil0_group 1 937 1 702 group_materi_elasti_young soil0_group 20 e3 group_materi_elasti_poisson soil0_group 0 3 group_materi_plasti_tension_direct soil0_group 1 0 group_materi_plasti_mohr_coul soil0_group 0 593 3 e0 0 105 group_groundflow_permeability soil0_group 0 1 0 1 Later when generating elements we will assign elements between y 6 and y 8 to group 0 and the elements below y 6 to group 1 Here for convenience and clarity we use a de fine of soil0 group for 0 and a define of soill_group for 1 One data records is new the group_materi_density_groundflow is used to specify the wet and dry density Tochnog will automatically use the wet density 1 937 20009 if it detects that an element of the group is below the phreatic level whereas the dry density 1 702 2000 48 will be used if the element is above the phreatic level Side remark for the group_groundflow_permeability we can use arbitrary values in this spe cific tutorial since the calculated groundwater pore pressure here will not be influenced by the permeability value start _define soill_group 1 end define group_type soill_group materi groundflow group_materi_memory soill_group total_linear group_materi_densi
13. 004 4 0 006 0 008 4 0 01 0 012 4 0 014 4 0 016 4 0 018 0 02 y y 1 1 05 14 1 15 12 1 25 1 3 Figure 4 Vertical displacement of post_point in time Clearly finally the slope becomes unstable 3 4 3 Plot results in Gid Open in Gid results View Postprocess File Open tutorial_1_flavia msh View Zoom In In Gid you first need to open the Gid results files as written by Tochnog and then zoom in to get the slope full in the figure Plot boundary conditions in Gid View results Display Vectors materi bounda dof All Tochnog also writes information about boundary conditions external forces etc in the Gid post processing files In the present example you can look in Gid at the boundary conditions with the command as given above Plot gravity results View results Default Analysis Step time 1 15 RE He ions t Boundary condi Figure 5 SISyy tress View results Contour Fill materi s 1 stress Vertica Figure 6 l stress field after lca Gid a contour filled plot of the vert An n These commands show how you obta gravity is imposed time 1 0 Plot safety results materi velocity All Lines P R R View results Default Analysis Step time 1 32 View results Display Vectors materi velocity Windows View Style Style dent ith reduced
14. Beam bending moment View Results Line Diagram Scalar beam force moment 5 Using a line diagram in Gid the beam moment can be displayed see figure You need to select beam force moment 5 since these values represent the moment around the z axis in the element_beam_force_moment record see the users manual 8 T T T sigxx 900 Using 3 2 f sigxx 910 using 3 2 poes NG n 2 rt 100 90 80 70 60 50 40 30 20 10 0 10 Figure 21 Pressure on sheet pile left and right gnuplot p sigxx 900 using 2 3 with linespoints sigxx 910 using 2 3 with linespoints set term postscript set output post_line_dof sigxx ps replot With Gnuplot an X Y graph of the soil pressures on the sheet pile is obtained see figure The second and third column from the sigxx 900 and sigyy 910 need to be used since those contain the y coordinate and the xx stress Notice the increase of the pressure near the end of the sheet pile As an exercise you can try to run the calculation with more elements to see how much results for the pressure on the sheet pile change with a finer mesh 37 6 Tutorial 4 excavation with sheet pile isoparametric and interface elements 6 1 Input file In this tutorial we show the same analysis as in tutorial 3 However in stead of truss beam elements we will use quad4 isoparametric elements to model the sheet pile And in stead of contact spring elements we will use quad interface element
15. TOCHNOG PROFESSIONAL Tutorial manual Version 23 Dennis Roddeman December 7 2015 Contents 1 Conditions 2 Basic information 3 Tutorial 1 slope safety factor analysis 3 1 Mesh generation with Gid de I hee a eG a A SU a eee Toi ie ee 3 2 1 Initialization part s sec serasa aaraa al ha Da tu Be eG pae ea Re ene ok ale pe RR Re a Ka ga ee eE rene 3 2 4 Data part gravity 6 ee 4 oe oie a Sa aaa aa A 3 2 6 Data part prepare post processing Rs de eee ras Beane Aes 3 2 9 Data part include mesh generated with Gid 3 2 10 Data part final remarks for advanced users 3 3 Run calculation e 4 4 4 fa 4 4 due da sun ee es Re ee Ra 3 4 Output results Rue wie 4 ae BAe EA ee ee Be bee eG BGS eS 3 4 1 Determine safety factor 3 4 2 Plot displacement history in Gnuplot 3 4 3 Plot results in GIA 4 Tutorial 2 non saturated dam with seepage edge 4 1 Mesh generation with Gid 4 Wnputnley ars ee eS bee oO Ee Oe Be a ee eae ave oie E 42 1 Initialization part o cae eor be Ph wa A Se wae ge RO 4 2 2 Data part geometry of edges 4 2 3 Data part some arithmetic expressions 4 2 4 Data part gravity gt lt c csa reseve didto t iri eatae 4 2 5 D
16. a end_define start define beam line geometry_line counter_a end_define start_define beam_short_line geometry_line counter_a end define beam_point 3 0 6 75 eps_geometry beam_line 3 0 2 0 3 0 8 0 eps_geometry beam_short_line 3 0 2 01 3 0 8 0 eps_geometry The beam_point defines the position of point A With beam_line we define a geometrical line completely along the sheet pile which will be used to automatically generate truss beam elements and contact springs The beam_line_short defines a geometry line a bit shorter than the sheet pile the purpose of this short line will become clear later The counter_a is a convenient way to give a unique index to each geometry without keeping tack of used numbers for indices yourself Initially the counter_a is 0 and each time it is used it will be automatically incremented with 1 by Tochnog So here beam_point geometry_point counter_a is be read as beam_point geometry_point 0 beam_line geometry_line counter_a is read as beam_line geometry_line 1 etc Since we later only will refer to the defined words beam_point beam_line etc those will be read as geometry_point 0 geometry_line 1 etc at each occurrence and there is no need to know the specific indices that are used 25 5 1 4 Data part edge geometries start define lower_edge geometry_line counter_a end_define start_define right_edge geometry_line counter_a end define start_define left_edge geometry_line counter_a end_define
17. a records group_beam_young and group_beam_shear Also for the truss force we apply small deforma tion theory as set by total linear in group truss memory The truss cross section area is specified in group_truss_area and the young modulus in group_truss_young 5 1 7 Data part boundary conditions bounda_dof 0 lower_edge vely bounda_dof 1 right_edge velx bounda_dof 2 left_edge velx bounda_dof 3 beam_point velx bounda_time 3 2 0 0 5 0 0 5 000001 0 005 1 e8 0 005 bounda_dof 4 all rotx roty In this calculation it is more convenient to prescribe velocities instead of prescribing displace ments since in the experiment the velocity of point A has been prescribed The bounda_dof 0 bounda_dof 1 and bounda_dof 2 specify conditions equal to the slope calculation of tutorial 1 The bounda_dof 3 needs more explanation It specifies the velocity of point A of the sheet pile in time Up to time 2 0 so during the first two excavations point A is not prescribed Then at time 2 0 it is fixed till time 5 0 so till the end of the loading at the top Then after time 5 0 point A gets a prescribed velocity of 0 005 so to the left The bounda_dof 4 suppresses two beam rotations which are not relevant in this 2D calculation only the rotz is relevant since it corresponds with in plane 2D bending of the beam There is one subtle but important remark to be made We impose the boundary condition for point A at the defined beam_point so
18. al flux is imposed automatically if you don t specify anything thus you don t see conditions at the bottom edge in the bounda_ records 4 2 7 Data part material properties start _arithmetic pe 1 e 5 DIVIDE rho DIVIDE g_absolute end_arithmetic The saturated permeability is 10752 Look however at the definition of the permeability for the input file in the user s manual A division by rho and g_absolute is needed this is easily accomplished with start_arithmetic end_arithmetic so that the input file remains readable group_type 1 groundflow group_porosity 1 0 5 group_groundflow_permeability 1 pe pe group_groundflow_nonsaturated_vangenuchten 0 0 0 1 2 49 0 140 1 507 The group_type is set to groundflow which means that the groundflow storage equation will solved in the elements The porosity is set to 0 5 with group_porosity For the saturated permeability the pe as calculated in the start_arithmetic end_arithmetic is used The group_groundflow_nonsaturated_vangenuchten records specifies the Van Genuchten law for non saturated groundwater properties 4 2 8 Data part prepare post processing post_calcul groundflow_pressure total_pressure post_node 0 node_rhside sum left_edge The post_calcul record takes care of calculating extra post processing data This calculated data becomes available for printing or for plotting in Gid See the user s manual for all possibilities of post_calcul Here post_calcul is used to
19. am is saturated whereas above the phreatic level the dam is non saturated In this calculation with group_groundflow_nonsaturated_vangenuchten the phreatic level follows automatically as a result of the calculation this is opposed to most geotechnical calculations where there are only fully saturated zones below an a priori known phreatic level which is specified in the input file 22 Plot the pore pressure in Gid View results Contour Fill topres Figure 11 Groundwater pore pressure in dam Plot the groundflow velocity in Gid View results Vectors groundflow velocity y Figure 12 Groundwater velocity in dam The vectors of groundflow velocity in figure clearly show that the flux exits the dam at a relatively small part of the left edge The highest node where groundwater starts to exit the dam is located at 6 98 3 81 23 5 Tutorial 3 excavation with sheet pile beam and contact spring elements This tutorial is taken from 2 An experiment is done with a sheet pile near an excavation The following is done e the sheet pile is completely inserted e two excavations are done e at point A the sheet pile is fixed in x direction in the experiment a horizontal strut is fixed to point A e three more excavations are carried out e the vertical load at the top surface is applied e point A of the sheet pile is moved to the left to find when the soil at the r
20. and interface elements purple post_calcul groundflow_pressure total_ pressure materi_stress force post_calcul_materi_stress_force_element_group sheet _pile group post_calcul_materi_stress_force_reference_point 100 4 The post_calcul materi_ stress force tells Tochnog that is should calculate forces and mo ments from initially calculated stresses The group for which this should be done is specified by post_calcul_materi_stress_force_element_group sheet_pile_group Finally it is needed to specify a reference point for drawing plots in GID so that positive and negative vectors for forces and moments are drawn in a unique manner 6 1 7 Data part timesteps Timesteps are much the same as in the previous tutorial We now take special action however in case the test_calculation is set to true In that case simply a timestep of size 1 is taken for imposing gravity and excavations In this way a linear test calculation can be performed very fast and you can check if linear results are plausible The lines below show how this is done start _define dtime 2 e 4 end_define start_if test_calculation control_timestep 700 1 1 0 end_if 41 start _if not test_calculation control timestep 700 dtime 1 0 end_if_ not The remaining part of the input file equals that of tutorial 3 6 2 Run calculation See tutorial 3 6 3 Output results View Results Display Vectors momsig Using a display vector in Gid the beam moment can
21. ar and you can find them in the input file tochnog test tutorial tutorial_3 dat The control _timestep 200 records specifies that time steps of size 1 e 2s should be taken until a time increment of 1 0s has been done This increment value of 1 0s is arbitrary since we do not use mass inertia in the calculation and so time is only a pseudo loading variable to specify the sequence of events in time With control_print 200 we ask for printing of the current time in the calculation and also the error ratio see tutorial 1 for a discussion on the error ratio or otherwise see the users manual The post_point_dof O disx denotes that from all post_point_dof records the one with index 0 should be used and from that record the first value should be taken numbering inside records starts of 0 in Tochnog The time_current 0 0 is a bit tricky since there is only one time_current record you need to specify a dummy 0 for the index and the second 0 denotes again the first value in the record so in fact the current time Now the first excavation area as specified by the geometry quadrilateral excavation_0 is actually excavated by the record 33 control_mesh_delete_geometry 200 record control_mesh_delete_geometry_element takes care that only quad4 soil elements will be excavated we don t want to excavate the truss_beam elements which are also located in the geometry quadrilateral control_reset_dof 330 disx disy In the experiment the report
22. ata part groundwater 10 10 11 12 12 13 13 13 14 14 14 14 15 17 4 2 6 Data part boundary conditions on edges 19 se an ne Paes nda Raed Bile eels 20 4 2 8 Data part prepare post processing 20 ia ST laa dede Bee a 21 des de De Aa A 21 4 2 11 Data part include mesh generated with Gid 21 godly dob Wea AU R ek Bee ahs 21 Lit nets GE bo IS we Phe AE erred AR TU AU 22 e a GO a Bh Bein y ele le a are a ee S 22 ee eee 22 4 4 2 Plot results in GIdl ee 22 5 Tutorial 3 excavation with sheet pile beam and contact spring elements 24 D Be ee ee we ee oe Ge ee ae eed ce ee ee ee 24 DLL Initialization partis 4 44 be Ra OE Re we ba paG a Pee Ee 24 Sit Bul gale DON amp Sores edhe E 25 oh ROM Oise PAN AG Sak aes ema Se 25 aR Daa baked a oh he tee GO we ES 26 9 1 5 Data part excavation geometries 26 DRE A NS CO ec Tee 27 a ie ere PAM a RE 28 5 1 8 Data part distributed force load on topl 28 9 1 9 Data part gravity 444488 29 La are E 29 5 1 11 Data part post processing and printing 29 5 1 12 Data part generate mesh with Tochnog 30 Homo eme A eee 31 BRL Re PT RER 33 wie donnaient E CU ee 34 boheme a ak dee d ess 34 a Geodon ad aa dd y a
23. be displayed see figure 23 You need to select momsig which is generated by the post_calcul commands TTT Display Vectors of momsig momsig factor 0 104585 Gil Figure 23 Beam bending moment 42 References 1 D V Griffiths P A Lane 1999 Slope stability analysis by finite elements Geotechnique 49 no 3 pp 387 403 2 I Shahrour S Ghorbanbeigi P A von Wolffersdorff 1995 Comportament des rideaux de palplanche experimentation en vraie grandeur et predictions numeriques Revue francaise de Geotechnique no 71 pp 39 47 43
24. by example in plane strain displacements in x and y also lead to oz However the stress matrix is symmetric so only 6 components need actually to be stored for the stress field the other components follow from symmetry In this slope stability calculation an elasto plastic material model will be used and thus initializa tion of the plastic strains materi_strain_plasti is needed After you have run the calculation you can always see in the data record dof_label in the database file in this case tutorial_1 dbs the component names of the initialized dof s disx and disy for the displacements materi_displacement etc 3 2 2 Data part geometry of edges start_define bottom_edge geometry_line 1 end_define start_define right_edge geometry_line 2 end_define start_define left_edge geometry_line 3 end_define We want to specify the edges at which boundary conditions are imposed later Each edge will be specified by a geometry line data record since the edges are straight lines It is convenient to define a name for each edge so that later that name can be used when needed and the input file remains more readable Each start_define end_define specifies a word by example bottom_edge which will be later substituted with its real meaning by example geometry_line 1 Such defines can be used for all kinds of input bottom_edge 0 0 0 0 60 0 0 0 0 01 left_edge 0 0 0 0 0 0 15 0 0 01 right_edge 60 0 0 0 60 0 5 0 0 01 The first
25. control_mesh_generate_truss_beam 80 record we generate the truss beam ele ments for the sheet pile line and should be assigned to the group sheet_pile_group The con trol_mesh_generate_truss_beam_loose 80 record tells Tochnog that the generated truss beam elements should not be fixed to the existing nodes of the quad4 elements but should get their own new nodes this will allow for slip between the sheet pile truss_beam nodes and the quad4 soil element nodes The control_mesh_generate_truss_beam_macro 80 record tells Tochnog that only truss elements should be placed near nodes which have been generated from a macro with index 10 or 20 if we would not do this then twice too much truss beam elements Contact springs between truss_beam nodes and quad4 nodes are generated with the con trol_mesh_generate_contact_spring 90 records Figures shows the generated mesh and gives a schematic drawing how the truss_beam elements are connected to the quad4 elements The detail drawing with the springs in figure 15 is really only for clarity in reality the nodes of the truss_beam elements and the quad4 elements have the same position in space but that would not give a very clear drawing 5 1 13 Data part set gravity stresses control_reset_dof 100 pres control_reset_value_constant 100 24 525 control_reset_dof 101 sigyy control_reset_value_multi_linear 101 0 0 114 825 2 5 91 85 8 0 0 0 control_reset_dof 102 sigxx sigzz control_reset_value_
26. d by running this tutorial if the real value at running the calculation differs from the expected value as set in target_item and target_value When distributing a new release we take care that tutorial calculations and also other calculations meet their expected values 21 4 3 Run calculation On Linux open a window and type tochnog tutorial 2 On Microsoft Windows open a DOS command prompt and type tochnog exe tutorial_2 After the calculation is ready you will see the following files in the directory e tutorial_2 dbs This is the database after the calculation It contains all information from the calculation input data results etc e tutorial_2_flavia msh and tutorial_2_flavia res Post processing files which can be opened with Gid e tochnog log Log file from Tochnog which lists the calculations that have been run 4 4 Output results 4 4 1 Value of the groundwater flux out of the left edge After the calculation the post_node_result 0 record in the tutorial_2 dbs contains the ground water flux out of the left edge as first value in the record The value is 1 45e 05 where the minus sign indicates that the flow goes outwards 4 4 2 Plot results in Gid Open the Gid post processing files in the usual way see tutorial 1 Plot the saturation in Gid View results Contour Fill groundflow saturation Figure 10 Groundwater saturation in dam From figure 10 is is clear that the lower part of the d
27. d in the record post_point_dof 10 Such post_point_dof record in turn can be used in several printing options 3 2 7 Data part apply gravity time steps control_timestep 10 1 e 1 1 0 control_print 10 time_current post_node_rhside_ratio control_print_gid 20 yes control_reset_dof 30 disx disy eppxx eppxy eppxz eppyy eppyz eppzz Time steps are actually started with control_timestep 10 There is one mportant topic about all control_ records that we need to discuss first These control_ records also have an in dex here the indices are 10 20 and 30 Specifically for control_ records these indices are important these records will be performed in order of increasing index Here that means that the records control_timestep 10 and control_print 10 are performed first after that the record control_print_gid 20 is performed and after that the record control_reset_dof 30 is performed The control_timestep 10 record tells Tochnog to take time steps of size 0 1 until a total time in crement of 1 0 is obtained The control_print 10 record specifies that some data records need to be printed specifically the current time time_current and the accuracy ratio post_node_rhside_ ratio The accuracy ratio contains the maximum out of balance force on a free node that is a node with out prescribed displacement divided by the maximum external force on a node with prescribed displacement Normally all printing during a calculation goes to the co
28. e remark if displacements are prescribed velocities automatically are calculated by Tochnog from the time derivative of the displacements If you would prescribe velocities with velx and vely then displacements automatically follow from time integration of the velocities Third side remark a list of all unknown names like disx etc can be found at dof_label in the users manual The dof_label is available in the database file after the calculation 3 2 4 Data part gravity force_gravity 0 0 10 force_gravity_time 0 0 0 0 0 5 1 0 1 e20 1 0 The gravity components as specified in force_gravity are 0 in x directions and 10 in y direction The force_gravity_time specifies at time versus factor diagram this is the factor with 10 which the gravity is applied It should be read as follows at time 0 0 the factor is 0 0 at time 0 5 the factor is 1 0 and up to time 1 e20 the factor remains 1 0 Later in this tutorial we will further discuss this topic so just go straight ahead with reading the next input Please realize that all input in Tochnog does not have a specific dimension The user just should take care that he she uses consistent units for the different input data but otherwise the units of input data is not pre defined 3 2 5 Data part material properties start _define phi 0 349065 end_define start _define tanphi 0 3639 end_define start_define c 10 0 end_define First we define the soil friction angle 0
29. ed displacements are relative to the deformations after the second excavation In the calculation this is obtained by the control_reset_dof record which sets the displacements to null after the second excavation 5 1 15 Data part apply load time steps control_timestep 700 1 e 2 1 0 control_print 700 time_current post_node_rhside_ratio post_node_result post_point_dof control_print_data_versus_data 700 time_current 0 0 post_point_dof 0 disx post_node_result 0 velx control print gid 720 separate_index Loading time steps of size 1 e 1s are taken till a time increment of 1 0s is reached The control_print_data_versus_data record is a convenient method to obtain from the calcu lation a text file containing several columns of information from whatever data records that you like Here it is used to get columns with the current time in the calculation the x displacement at point A and the reaction force at point A When the loading steps are ready we print Gid plotting files with control_print_gid 720 5 1 16 Data part apply velocity point A time steps control timestep 700 5 e 2 1 control_print 700 time_current post_node_rhside_ratio post_node_result post_point_dof control_print_data_versus_data 700 time_current 0 0 post_point_dof 0 disx post_node_result 0 velx control_print_gid 720 separate_index 5 1 17 Data part print pressure on beam control_print_dof_line 900 yes control_print_dof_line_coordinates
30. eet pile The sheet pile refuges to be compressed because it is very stiff so the sheet pile displacement vector is nearly horizontal The soil slips over the sheet pile so the displacement vector of the soil points also downwards Windows View Results Main Mesh Deformed Materi Mesh Deform It is in Gid also possible to draw the deformed FE mesh In figure 18 we used a factor of 20 to get a clear view of the deformations Windows View Results Main Mesh Original Set the mesh back to original to draw the undeformed mesh again View Results Contour Fill Materi plasti kappa 35 y y Figure 18 Deformed mesh Figure 19 Material effective plastic strain kappa 36 001016 10 0090309 0 007902 0 0067732 00056443 00045154 10 0033866 0 022577 0 001 1289 o The effective plastic strain shows the Mohr Coulomb shear failure line caused by moving the sheet pile at point A to the left see 19 y Figure 20
31. erface 0 5 x tan phisoi start _define interface_group 3 end define group_type interface _group materi group_interface interface_group yes group interface_materi_memory interface_group total_linear group interface_materi_elasti_stiffness interface_group 10 e10 5 e10 group interface materi plasti mohr coul direct interface group 0 4636 1 0 group_interface materi_plasti tension interface group no For convergence of the calculation it is required to use a quite small interface stiffness 6 1 5 Data part generate mesh with Tochnog The commands for mesh generation are as follows 39 control _mesh_macro 10 rectangle soill_group 7 9 control mesh_macro_parameters 10 1 5 1 0 3 0 2 0 control mesh_macro_element 10 quad4 control_mesh_macro 20 rectangle soill_ group 7 17 control_mesh_macro_parameters 20 1 5 4 0 3 0 4 0 control_mesh_macro_element 20 quad4 control_mesh_macro 30 rectangle soil0_ group 7 9 control_mesh_macro_parameters 30 1 5 7 0 3 0 2 0 control_mesh_macro_element 30 quad4 control _mesh_macro 40 rectangle soill_group 2 9 control mesh macro parameters 40 3 05 1 0 0 1 2 0 control mesh_macro_element 40 quad4 control _mesh_macro 50 rectangle sheet_pile_ group 2 17 control mesh_macro_parameters 50 3 05 4 0 0 1 4 0 control mesh macro element 50 quad4 control_mesh_macro 60 rectangle sheet _pile_ group 2 9 control mesh_macro_parameters 60 3 05 7 0 1 2 0 control_mesh_macro_element 60 quad4 control_m
32. esh_macro 70 rectangle soill_group 28 9 control_mesh_macro_parameters 70 7 55 1 0 8 9 2 0 control_mesh_macro_element 70 quad4 control_mesh_macro 80 rectangle soill_group 28 17 control_mesh_macro_parameters 80 7 55 4 0 8 9 4 0 control_mesh_macro_element 80 quad4 control_mesh_macro 90 rectangle soil0_group 28 9 control_mesh_macro_parameters 90 7 55 7 0 8 9 2 0 control_mesh_macro_element 90 quad4 control_mesh_merge 95 yes control_mesh_generate_interface 96 interface_group soil0_group sheet _pile_group control_mesh_generate_interface 97 interface_group soill_group sheet_pile_group The generation of the sheet pile group is new see control index 50 and 60 it generates quad4 isoparametric elements which model the sheet pile Further look how simple the interfaces between the sheet pile group and soil group are generated see control index 96 and 97 it generates quad4 interface elements which model the sliding between soil and sheet pile Figure 22 shows the generated mesh 6 1 6 Data part post processing and printing In this tutorial we use isoparametric quad4 elements to model the sheet pile Isoparametric elements primarily calculate stresses so that forces and moments are not directly available To get the forces and moments in the sheet pile a post calculation is needed The following post_calcul commands perform this calculation 40 Figure 22 Mesh with soil elements green black sheet pile elements blue
33. he right of the sheet pile Again we merge the top and bottom mesh at the common line at y 6 0 control_mesh_merge 70 yes 30 control mesh_merge_macro_generate 70 10 40 control_mesh_merge_not 70 beam_short_line Up to now we only merged rectangular meshes along y 6 0 so at their common horizontal line Here we merge the left and right meshes at their common line along x 3 0 However to allow for slip along the sheet pile we do not want to merge nodes along the location of the sheet pile so that slip and different displacements at the sheet pile remains possible Thus the merging with index 70 is not done at the sheet pile by including control_mesh_merge_not 70 In fact we use a geometrical line a bit shorter than the actual length of the sheet pile The reason for this is that the nodes at the end of the sheet pile can either be considered to be part of the sheet pile or part of the soil underneath the sheet pile We prefer to consider these nodes the be part of the soil underneath the sheet pile and so prefer to merge these nodes control_mesh_generate_truss_beam 80 sheet_pile_group beam_line control mesh generate truss beam loose 80 yes control mesh _generate_truss_beam_ macro 80 10 20 control_mesh_generate_contact_spring 90 contact_spring_group beam_line control_mesh_generate_contact_spring_element 90 quad4 truss_beam With the previous macro and merge records we have generated quad4 elements for the soil Here with the
34. ied to this kind of calculation first a linear solution is established and afterwards the full nonlinear solution is searched iteratively with the linear solution as first guess We obtain a linear calculation with the extra records control_groundflow_nonsaturated_apply 10 and control_groundflow_seepage_apply 10 These records de activate the group_groundflow_nonsatu and groundflow_seepage_geometry for the time steps of control_timestep 10 Notice that we print the current time time_current and the error ratio post_node_rhside_ratio The error ratio is the ratio of the maximum out of balance flux at nodes without free hydraulic head and the maximum flux at nodes with prescribed hydraulic head 4 2 10 Data part apply nonlinear time steps control_timestep 20 1 100 control_print 20 time_current post_node_rhside_ratio After the linear solution was obtained with control_timestep 10 the time steps as specified in control_timestep 20 are used to find the nonlinear solution including non saturation and the seepage condition on the left edge 4 2 11 Data part include mesh generated with Gid include mesh gid mesh dat 4 2 12 Data part final remarks for advanced users target_item 1 post_node_result 0 0 target_value 1 1 45083e 05 1 e 7 Here we check with target_item and target_value that the flux of groundflow to the left edge has the expected value In case a new Tochnog release would have a bug that will be automatically detecte
35. ight of the sheet pile will become unstable 3 1 4 4 Ix gt lt gt gt lt gt FATTATIE 1 1 25 la Y y i material 1 2 f0 75 At i ka 1 25 Ka Y z material 2 4 BD Ka a ate Le 3 5 1 D KA D y KE y A D I Ka D ka 2 5 D K Y Figure 13 Excavation with sheet pile The dimension are given in figure 13 At the left side of the sheet pile you see the five excavations levels All excavations remain above the phreatic water level which you can see at y 2 5 Especially notice point at which the sheet pile after the second excavation is supported and later is moved to the left 5 1 Input file 5 1 1 Initialization part echo yes number_of space_dimensions 2 materi_velocity materi_displacement materi_strain_plasti materi_plasti_kappa 24 materi_ stress groundflow_pressure beam_rotation end_initia Notice in the initialization part that we initialized materi_ for an elasto plastic calculation together with groundflow_pressure for groundwater pressure analysis Additionally for the sheet pile we will use truss beam elements so that we also need to initialize beam_rotation 5 1 2 Data part tolerance on geometries start_arithmetic eps_geometry 1 e 5 end_arithmetic For convenience we define eps_geometry 1 e 5 which will be used later as tolerance for geome tries 5 1 3 Data part beam geometries start _define beam_point geometry_point counter_
36. l fields for the groundwater pressure and material stresses at the start of the calculation with control_dof_reset records so that the gravity makes equilibrium with the pressure and stresses 5 1 10 Data part groundwater properties groundflow_density 1 0 groundflow_phreatic_level 0 0 2 5 15 0 2 5 The groundwater density is 1 01 The level of groundwater is constant between x 0 0m y 2 5m and x 15 0m y 2 5m 5 1 11 Data part post processing and printing post_point 0 3 0 6 75 post_node 0 node_rhside sum beam_point post_calcul groundflow_pressure total_pressure print_gid_contact_spring2 1 To obtain exactly at point A information about the solved solutions fields displacements stresses etc we specify post_point 0 at 3 0 6 75 Tochnog will then automatically find out where in the FE mesh this post point is located and calculates there the solution field by interpolating results from the specific element in which the post point is located These results will be placed in the record post_point_dof which in turn is available in the database after the calculation or can be printed with control_print or control_print_data_versus_data during the calculation The post_node 0 record sums the node_rhside record on all nodes present in the geometry beam_point so in this case we directly get the node_rhside record at the node located at point A The node_rhside contains for nodes with prescribed velocity or displacement
37. line bottom_edge 0 0 0 0 60 0 0 0 0 01 is read by Tochnog as geometry_line 1 0 0 0 0 60 0 0 0 0 01 so in fact geometry_line 1 is specified The other two lines specify geometry_line 2 and geometry_line 3 The 0 01 indicate the tolerance of the lines all nodes in the model with a distance not more than 0 01 are considered to be located on the geometrical lines Notice that we identify each geometry_line by a unique index for the present geometry lines the indices 1 2 and 3 are used In fact most of the data in the input file uses an index by example element data records use an index which is the element number node data records use an index which is the node number etc 3 2 3 Data part boundary conditions bounda_dof 0 bottom_edge disx disy bounda_dof 1 left_edge disx bounda_dof 2 right_edge disx The bounda_dof records are used to prescribe unknowns dof s On the bottom edge the dis placement in x direction disx and the displacement in y direction disy are suppressed and on the left edge and right edge the displacement in x direction disx is suppressed The nice thing about using geometries for boundary conditions is that these remain valid even if you change the mesh amount of elements nodes First side remark if we want to apply a non zero displacement then also the bounda_time records should be specified here however displacements on the edges are zero and then the bounda_time records are not needed Second sid
38. me steps to determine where between time 1 and 2 the slope becomes unstable The records control_timestep 40 with control_timestep_iterations_automatic 40 together define automatic time steps which will be taken till instability occurs The record control_timestep defines an initial timestep of 1 e 4 and total time increment of 1 0 The record control_timestep_iterations_automatic specifies that the maximum allowed value of the error ratio post_node_rhside_ratio is 1 e 3 the minimum allowed time step size is 1 e 5 and the max imum allowed time step size is 1 e 2 Tochnog will decrease the time step size if that is needed to keep the error ratio below 1 e 3 If that is not possible anymore due to instability caused by low friction angle and cohesion the calculation is terminated Later we will discuss how using the current time of the terminated calculation the safety factor can be calculated 3 2 9 Data part include mesh generated with Gid include mesh gid mesh dat The include command allows you to include other files containing data records in the current input file Here the mesh data as generated with Gid is included 3 2 10 Data part final remarks for advanced users solver_matrix_save always Default Tochnog will completely setup and decompose the system matrix when it thinks the matrix is changed In the present calculation some material data is changed the friction angle and cohesion and so Tochnog will setup and decompose the
39. mputer monitor but the advanced user can redirect printed output to a file Now look back at how we defined the gravity in time It was increased from 0 0 at time 0 0 to its final value of 10 at time 0 5 Thus the time increment of 1 0 is enough for getting gravity imposed 12 from time 0 0 to time 0 5 and also allows the equilibrium with full gravity to be established accurately with additional time steps from time 0 5 to time 1 0 The control _print_gid 20 record takes care that the results at the end of gravity are printed in the tochnog_flavia msh and tochnog_flavia res files These can be post processed with Gid Finally to prepare the safety factor calculation itself some results are set to 0 0 in order to be able to distinguish clearly after the safety factor calculation between safety factor results instability results and gravity results To be specific the displacement components disx disy are set to 0 0 and the components of the plastic strains eppxx eppxy eppxz eppyy eppyz eppzz are set to 0 0 3 2 8 Data part apply safety factor calculation time steps control_timestep 40 1 e 4 1 0 control_timestep_iterations_automatic 40 1 e 3 1 e 5 1 e 2 control_print 40 time_current post_node_rhside_ratio control_print_history 40 post_point_dof 10 disy control_print_gid 50 yes Look first back at the material definition where the friction angle and cohesion are lowered between time 1 and time 2 We will now use ti
40. multi_linear 102 0 0 49 21071429 2 5 39 36428571 8 0 0 0 31 PP isdie si se h Figure 14 Mesh with quadrilateral elements truss beam and contact springs Figure 15 Model of slip at beam with springs 32 control_print_gid 120 separate_index The control reset _dof 100 and control reset_ value constant 100 records together set a con stant hydraulic head of 24 525 consistent with the phreatic level at y 2 5m The con trol_reset_dof 102 and control_reset_value_multi_linear 1012 records together set the multi linear gravity field for the stresses 12 758 25517 38275 51 033 63 792 7655 89 308 102 07 114 82 y Figure 16 Gravity vertical stress field sigyy Plot 16 shows the vertical stress as plotted with Gid 5 1 14 Data part apply excavation time steps control timestep 200 1 e 2 1 0 control_print 200 time_current post_node_rhside_ratio control_mesh_delete_geometry 200 excavation_0 control_mesh_delete_geometry_element 200 quad4 control_print_data_versus_data 210 time_current 0 0 post_point_dof 0 disx post_node_result 0 velx control_print_gid 220 separate_index We discuss here how the first excavation can be done in Tochnog the other excavations are done quite simil
41. oup material Select GROUP1 in the dialog and set the group_type to materi Then select the surface with Assign Surfaces Generate a mesh with linear triangles 10n Mesh of slope ials mater t essentially specifies which unknown ion par itializat inl Nurbs surface of slope Figure 2 Gid uses as default element type for surfaces linear triangles which are OK for the slope stability analysis Hence we don t need to change the element type and can go straight on to generate the Mesh Generate mesh mesh arc rat AN res ADA ES 6 DO ERA LOGO COCOON RIC LR ACROSS CRESS CROSS RON RO ES to 0 5 gives a fine mesh good enough for an accurate solut 1Ze RE SORA OR RED ARAN RS AY RARA AAA AA AAA PAIN el E Setting the element s Figure 3 gi 1 8 mesh id data To really obtain the generated mesh in a file that can be used for Tochnog calculate the Tochnog file Please realize that this option in Gid only calculates the Tochnog input file for the mesh and not does the FE calculation itself solving equations In the directory mesh gid you can find the file mesh dat which contains element element_group and node data the node numbers to which the element is connected The element_group records contain for each element the group number which contains material properties for the element The node The element data records
42. roperties The material properties for the soil are the same as in tutorial 3 For the sheet pile we will use isoparametric quad4 elements with a large fictive thickness As density we simply take the soil density we is OK since most of the fictive thickness in reality will actually consist of soil The young modulus we fitted in such way that the bending behavior of the isoparametric quad4 elements is the same as that of the truss_beam elements of tutorial 3 in fact we have simply put a force at the bottom of the quad4 elements and truss_beam elements and tuned the young modulus of the quad4 elements such that the same displacement was obtained with both models start_define sheet_pile_group 2 end_define group_type sheet_pile_group materi group_materi_memory sheet_pile_group total_linear group_materi_density sheet_pile_group 1 702 group_materi_elasti_young sheet_pile_group 5 9874e6 For the slip between soil and sheet pile we will use interface elements The stiffness of interface elements should be taken high enough so that the deformations in the interface elements are relatively small On the other hand the stiffness of interface elements should not be too large because that would lead to a bad conditioned matrix and numerical problems The interfaces are not allowed to transfer tension stresses and slip frictional forces are restricted by a Mohr Coulomb law the friction angle of the Mohr Coulomb law is taken such that tan phiint
43. rs 10 and control_mesh_macro_element we specify that a rectangular mesh should be generated with quad4 elements and the elements should be assigned to group 1 The rectangle has middle point x 1 5 y 3 0 width 3 0 and height 6 0 the number of nodes in width direction so x direction is 7 and the number of nodes in height direction so y direction is 25 Similar the records with index 20 generate a second rectangular mesh These 10 and 20 records together generate the left part of the mesh that is all quad4 elements to the left of the sheet pile The two rectangular meshes each have nodes at a common line y 6 0 so in fact there are duplicate nodes at this line The control_mesh_merge 20 takes care that these duplicate nodes are merged so that at the common line the meshes connect to the same nodes and solution field like velocities displacement and water pressure are continuous With control mesh merge macro generate 20 we ensure that the meshes as specified with the macro s with index 10 and 20 are merged control_mesh_macro 40 rectangle soill_group 28 25 control_mesh_macro_parameters 40 7 5 3 0 9 0 6 0 control_mesh_macro_element 40 quad4 control_mesh_macro 50 rectangle soil0_group 28 9 control_mesh_macro_parameters 50 7 5 7 0 9 0 2 0 control_mesh_macro_element 50 quad4 control_mesh_merge 60 yes control_mesh_merge_macro_generate 60 40 50 With the macro s with indices 40 and 50 rectangular meshes are generated to t
44. s taken from example 2 in I The safety factor of a slope is calculated 20 20 20 lt gt gt lt gt 7 VTT TTTTTTITT I TT TT TT TT TT TT TT TT TTITTITTITT 7 kl ke gt Figure 1 Slope Figure 1 shows the slope The lower edge is completely fixed whereas at the left and right edge free sliding in vertical direction is allowed 3 1 Mesh generation with Gid Although Tochnog contains some build in mesh generation here for generality the external Pre and Postprocessor Gid is used Start Gid and perform the following steps Specify the Tochnog problem type in Gid Data Problem type Tochnog This takes care that Gid understands that you want to generate a mesh for Tochnog Some Tochnog specific input is now available and once the mesh is generated it can be written in a file in Tochnog specific format Create points lines and a surface in Gid Geometry Create Point Create the points along the entire edge of the slope thus 0 0 60 0 60 5 40 5 20 15 and 0 15 Zoom Frame Zoom to the total frame to see all points Geometry Create Straight Line Use the points to create the straight lines along the entire edge Geometry Create Nurbs surface By contour Use the straight lines to create a surface Figure 2 shows the Nurbs surface Assign a material to the surface Data Materials Assign Surfaces Now assign to the surface a Tochnog element gr
45. s to model the slip between sheet pile and soil We will not repeat all the details of the analysis only the differences with tutorial 3 will be highlighted 6 1 1 Initialization part echo yes number_of_space_dimensions 2 materi_velocity materi_displacement materi_strain_plasti materi_plasti_kappa materi_stress groundflow_pressure end _initia Please notice that we did not initialize beam_rotation since will be not use truss beam elements in this tutorial 6 1 2 Data part using linear test calculations We included the definition of test_calculation which we either set to true or false Then using start_if test_calculation end_if we can perform a fast linear test calculation when test_calculation is set to true In this way it is easy to test whether the excavations go well under linear elastic conditions no plasticity etc and check if linear elastic displacements stresses etc are plausible Once the linear elastic calculation is verified the test_calculation can be set to false and the full non linear calculation can be done You are encouraged to follow the same strategy start_define test_calculation false end_define start_if test_calculation linear_calculation_apply yes end _if 38 6 1 3 Data part geometries Since we will not use truss beams the beam geometries in the data part do not need to be defined Only the edge geometries and excavation geometries are defined 6 1 4 Data part material p
46. system matrix at all time steps between time 1 0 and 2 0 You can impose however that the matrix will not be setup and decomposed each time step by using solver_matrix_save always then the decomposed matrix is saved once 13 and used again at the next time step This can save considerable computing time This typically is useful for safety factor calculations but otherwise should only be used with care target _item 10 time_current 0 0 target_value 10 1 0 2 e 2 The records target_item and target_value are a convenient method to check if critical results of a calculation do change With target_item you specify which result should be checked and with target_value you specify the expected value maximum allowed deviation from the result In case the real value differs more from the expected value here 1 0 then the maximum deviation here 2 e 2 an error message is printed in the file tochnog log In this way you can make your own set of calculations which are important for your applications and check with each new tochnog release if results are still like you expect them to be 3 3 Run calculation On Linux open a window and type in the directory with the tutorial 1 input file the command tochnog tutorial_1 On Microsoft Windows open a DOS command prompt and type in the directory with the tutorial 1 input file the command tochnog exe tutorial_1 After the calculation is ready you will see the following extra files in the directory
47. the entire domain Initialization of the saturation rate is done with groundflow_saturation This is needed since a non saturated water model will be used It is convenient to have the ground flow velocity vectors available for interpretation of the results and thus we initialize ground flow_velocity 4 2 2 Data part geometry of edges start_define eps_geometry 1 e 1 end_define start_define left_edge geometry_line 10 end define left_edge 0 0 55 30 eps_geometry start_define right_dry_edge geometry_line 20 end define right_dry_edge 135 20 120 30 eps_geometry We define geometrical lines where later the water boundary conditions will be applied 4 2 3 Data part some arithmetic expressions start _arithmetic rho 1 0 end_arithmetic 18 start_arithmetic g 10 0 end_arithmetic start_arithmetic g_absolute 10 0 end_arithmetic Here some parameters are specified with start_arithmetic end_arithmetic The advantage of such arithmetic definitions for floating point parameters that is real values is that these later can be used with build in arithmetic operators in the Tochnog input file reader to calculate new parameters which in turn can be used in the input file Just read on to see how this is used here 4 2 4 Data part gravity force_gravity 0 0 g The gravity components as specified in force_gravity are 0 in x directions and 10 in y direction Notice that the g as specified above with the arithmetic has
48. the external reaction force on the prescribed node for the positions in the node_rhside record that matches the velocity unknowns so position 0 and 1 in this calculation see dof_label in the database after the calculation The result for post_node O will be placed in the record post_node_result 0 which again can be viewed in the database after the calculation or printed during the calculation Similar to the dam calculation in tutorial 2 we need a post_calcul groundflow_pressure total_pressure 29 Finally with print_gid_contact_spring2 1 we require that Gid plots the contact springs as one node elements even if they are in the calculation really two node elements this is done because Gid draws two node elements with their length and since the length of the contact springs is 0 the contact springs would become invisible when drawn with two nodes 5 1 12 Data part generate mesh with Tochnog control_mesh_macro 10 rectangle soill_group 7 25 control_mesh_macro_parameters 10 1 5 3 0 3 0 6 0 control_mesh_macro_element 10 quad4 control_mesh_macro 20 rectangle soil0_group 7 9 control_mesh_macro_parameters 20 1 5 7 0 3 0 2 0 control_mesh_macro_element 20 quad4 control_mesh_merge 30 yes control mesh_merge_macro_generate 30 10 20 Tochnog has some build in mesh generation possibilities which are convenient for relatively easy meshes If the mesh is complex Gid works better With control_mesh_macro 10 control_mesh_macro_paramete
49. ty_groundflow soill_group 1 937 1 702 group_materi_elasti_young soill_group 30 e3 group_materi_elasti_poisson soill_group 0 3 group_materi_plasti_tension_direct soill_group 1 0 group_materi_plasti_mohr_coul soill_group 0 698 3 e0 0 209 group_groundflow_permeability soill_group 0 1 0 1 For group 1 we define a soill_group start define sheet _pile_ group 2 end_define group_type sheet_pile_group truss_beam group_beam_memory sheet_pile_group total_linear group_beam_inertia sheet_pile_group 2 085e 4 2 085e 4 1 group_beam_young sheet_pile_group 9 87e6 27 group_beam_shear sheet _pile_ group 9 87e6 group_truss_memory sheet_pile_group total_linear group_truss_area sheet_pile_group 0 223 group _truss young sheet pile group 9 87e6 Later truss beam elements will be generated for the sheet pile and these truss beam elements will be assigned to group 2 For this group 2 we define a sheet _pile_ group The group_type is set to truss_beam so that both truss forces and beam moments will be calculated Setting total_linear for group_beam_memory indicates that small deformation theory needs to be used for the beam moments and forces The beam area moments of inertia and polar moment of torsion are specified in group_beam_inertia in fact the polar moment of torsion can be a dummy value since torsion is not relevant in this specific calculation The beam young mod ulus and shear modulus for the torsion moment calculation are specified in the dat
Download Pdf Manuals
Related Search