# \#flac3d **URL:** https://forum.itascainternational.com/tag/flac3d/14.md [Latest](https://forum.itascainternational.com/latest.md) · [Categories](https://forum.itascainternational.com/categories.md) · [Tags](https://forum.itascainternational.com/tags.md) --- ## [How to Start Post-Shake Consolidation After Compliant-Base Dynamic Analysis in FLAC2D?](https://forum.itascainternational.com/t/how-to-start-post-shake-consolidation-after-compliant-base-dynamic-analysis-in-flac2d/2386)
**Author:** [@EmirhanAltinok](https://forum.itascainternational.com/u/EmirhanAltinok)\ **Replies:** 5\ **Last updated:** [September 16, 2026, 5:46pm UTC](https://forum.itascainternational.com/t/how-to-start-post-shake-consolidation-after-compliant-base-dynamic-analysis-in-flac2d/2386 "2026-09-16T17:46:39Z")
Hello all, I am performing nonlinear dynamic effective-stress SSI analyses in FLAC2D 9.0 using PM4Sand and PM4Silt. The model includes two buildings represented by elastic beam elements. The earthquake motion is applied … --- ## [Spatially variable soil layers in FLAC 3D](https://forum.itascainternational.com/t/spatially-variable-soil-layers-in-flac-3d/2404)
**Author:** [@Milads](https://forum.itascainternational.com/u/Milads)\ **Replies:** 1\ **Last updated:** [August 11, 2026, 12:54pm UTC](https://forum.itascainternational.com/t/spatially-variable-soil-layers-in-flac-3d/2404 "2026-08-11T12:54:22Z")
I am working with a 3D model that has a spatially varying soil profile. What is the recommended method for assigning soil layer groups? Can soil layers be interpolated from a few 2D cross sections? Any example workflows … --- ## [Can a time varying external load applied to a saturated soil mass generate excess pore pressure when using Mohr-Coulomb in a coupled fluid-mechanical analysis?](https://forum.itascainternational.com/t/can-a-time-varying-external-load-applied-to-a-saturated-soil-mass-generate-excess-pore-pressure-when-using-mohr-coulomb-in-a-coupled-fluid-mechanical-analysis/2395)
**Author:** [@Sudipta](https://forum.itascainternational.com/u/Sudipta)\ **Replies:** 0\ **Last updated:** [June 15, 2026, 5:21pm UTC](https://forum.itascainternational.com/t/can-a-time-varying-external-load-applied-to-a-saturated-soil-mass-generate-excess-pore-pressure-when-using-mohr-coulomb-in-a-coupled-fluid-mechanical-analysis/2395 "2026-06-15T17:21:35Z")
Hello @everyone, @itascaYang @isaac @itsmoho\_sen @ITE @itascaYang @itasca @dafo407\_itasca @ddegagne @dblanksma @itmam I am running a coupled fluid–mechanical FLAC3D model using the Mohr-Coulomb constitutive model. I hav… --- ## [Applying Time-Varying Non-Uniform Surface Pressure in FLAC3D](https://forum.itascainternational.com/t/applying-time-varying-non-uniform-surface-pressure-in-flac3d/2390)
**Author:** [@Sudipta](https://forum.itascainternational.com/u/Sudipta)\ **Replies:** 0\ **Last updated:** [June 2, 2026, 5:18pm UTC](https://forum.itascainternational.com/t/applying-time-varying-non-uniform-surface-pressure-in-flac3d/2390 "2026-06-02T17:18:27Z")
Hello everyone and Itasca support team, @itascaYang @isaac @itsmoho\_sen @ITE @Inwoo @Inu @itmam @itasca @dafo407\_itasca @dblanksma I am trying to apply a time-varying non-uniform distributed pressure on a surface in FL… --- ## [Questions About Fully Coupled Flow–Mechanical Analysis and Solution-Control Parameters in FLAC3D](https://forum.itascainternational.com/t/questions-about-fully-coupled-flow-mechanical-analysis-and-solution-control-parameters-in-flac3d/2389)
**Author:** [@Sudipta](https://forum.itascainternational.com/u/Sudipta)\ **Replies:** 0\ **Last updated:** [June 1, 2026, 3:48pm UTC](https://forum.itascainternational.com/t/questions-about-fully-coupled-flow-mechanical-analysis-and-solution-control-parameters-in-flac3d/2389 "2026-06-01T15:48:49Z")
Hello @everyone, @itascaYang @isaac @itsmoho\_sen @ITE @Inwoo @Inu @itasca @dafo407\_itasca @itascan I am planning to perform a fully coupled flow–mechanical analysis in FLAC3D. My current understanding of the command seq… --- ## [Guidance on Introducing Fluid, Biot Coupling, and Water Table for Mechanical Pore Pressure Generation in FLAC3D](https://forum.itascainternational.com/t/guidance-on-introducing-fluid-biot-coupling-and-water-table-for-mechanical-pore-pressure-generation-in-flac3d/2388)
**Author:** [@Sudipta](https://forum.itascainternational.com/u/Sudipta)\ **Replies:** 0\ **Last updated:** [May 29, 2026, 2:55am UTC](https://forum.itascainternational.com/t/guidance-on-introducing-fluid-biot-coupling-and-water-table-for-mechanical-pore-pressure-generation-in-flac3d/2388 "2026-05-29T02:55:47Z")
Hello @everyone, @itascan @itascaYang @itasca @dafo407\_itasca @itsmoho\_sen @isaac I am trying to introduce fluid behavior and Biot coupling in a FLAC3D model so that pore pressure can be generated when external loading … --- ## [Wetting Induced Deformation Simulation- Infiltration result questionable](https://forum.itascainternational.com/t/wetting-induced-deformation-simulation-infiltration-result-questionable/2381)
**Author:** [@Adams](https://forum.itascainternational.com/u/Adams)\ **Replies:** 0\ **Last updated:** [May 8, 2026, 6:53pm UTC](https://forum.itascainternational.com/t/wetting-induced-deformation-simulation-infiltration-result-questionable/2381 "2026-05-08T18:53:52Z")
Hi, I am trying to simulate a wetting induced deformation of an embankment. I used FISH function to couple the hydraulic and stress strain behavior using Modified Cam Clay as the mechanical constitutive model and hydraul… --- ## [Difficulty with staged embankment construction using Modified Cam Clay in FLAC3D (yield envelope error)](https://forum.itascainternational.com/t/difficulty-with-staged-embankment-construction-using-modified-cam-clay-in-flac3d-yield-envelope-error/2376)
**Author:** [@Adams](https://forum.itascainternational.com/u/Adams)\ **Replies:** 2\ **Last updated:** [April 21, 2026, 7:48pm UTC](https://forum.itascainternational.com/t/difficulty-with-staged-embankment-construction-using-modified-cam-clay-in-flac3d-yield-envelope-error/2376 "2026-04-21T19:48:14Z")
I am attempting to simulate a compacted highway embankment in FLAC3D following the general framework for unsaturated hydro-mechanical behavior of compacted fill. My workflow involves staged construction of the embankment… --- ## [Suppress pop up dialog](https://forum.itascainternational.com/t/suppress-pop-up-dialog/2330)
**Author:** [@JuDi](https://forum.itascainternational.com/u/JuDi)\ **Replies:** 2\ **Last updated:** [February 16, 2026, 8:59am UTC](https://forum.itascainternational.com/t/suppress-pop-up-dialog/2330 "2026-02-16T08:59:57Z")
Hi, is there a way to suppres these pop up dialogs when running a data file the change in state is not relevant in this context. Any hint appreciated. Julia --- ## [Interpreting FOS results with fault interfaces in FLAC3D](https://forum.itascainternational.com/t/interpreting-fos-results-with-fault-interfaces-in-flac3d/2284)
**Author:** [@Luca86](https://forum.itascainternational.com/u/Luca86)\ **Replies:** 5\ **Last updated:** [January 21, 2026, 12:45pm UTC](https://forum.itascainternational.com/t/interpreting-fos-results-with-fault-interfaces-in-flac3d/2284 "2026-01-21T12:45:43Z")
Hi everyone, I am currently running a model of an open pit with faults using FLAC3D v7. The geological units were imported as DXF files, while the faults were added as planar structures via Griddle and defined as interf… --- ## [Suggestions for Scale Box plot item](https://forum.itascainternational.com/t/suggestions-for-scale-box-plot-item/2311)
**Author:** [@Anorriz](https://forum.itascainternational.com/u/Anorriz)\ **Replies:** 1\ **Last updated:** [January 11, 2026, 1:47am UTC](https://forum.itascainternational.com/t/suggestions-for-scale-box-plot-item/2311 "2026-01-11T01:47:37Z")
Hello dear colleagues, I’ve been using the Scale Box plot item lately, and I find it very useful. However, it would be great to have more control over it—specifically, the ability to display the Scale Box labels not on… --- ## [Request for Guidance on Plastic Multiplier Calculation for Constitutive Model in FLAC3D](https://forum.itascainternational.com/t/request-for-guidance-on-plastic-multiplier-calculation-for-constitutive-model-in-flac3d/2173)
**Author:** [@MojtabaNematollahi](https://forum.itascainternational.com/u/MojtabaNematollahi)\ **Replies:** 7\ **Last updated:** [December 2, 2025, 2:32am UTC](https://forum.itascainternational.com/t/request-for-guidance-on-plastic-multiplier-calculation-for-constitutive-model-in-flac3d/2173 "2025-12-02T02:32:12Z")
Dear Colleagues, I am currently developing a new constitutive model that incorporates a curved yield surface, conceptually similar to the Drucker-Prager criterion. My current challenge lies in determining the plastic mu… --- ## [Bug with the export to vtk of FLAC3D](https://forum.itascainternational.com/t/bug-with-the-export-to-vtk-of-flac3d/2238)
**Author:** [@stephaneBeaussier](https://forum.itascainternational.com/u/stephaneBeaussier)\ **Replies:** 5\ **Last updated:** [September 25, 2025, 12:56pm UTC](https://forum.itascainternational.com/t/bug-with-the-export-to-vtk-of-flac3d/2238 "2025-09-25T12:56:22Z")
Dear all, There seems to be an issue with the export of results to vtk in FLAC3D version 9.4.33 on Window 11. I created below a minime viable example: model new zone create brick zone vtk filename “testfile“ This… --- ## [Short-Period Spike in PSA from Plastic Hardening Model](https://forum.itascainternational.com/t/short-period-spike-in-psa-from-plastic-hardening-model/2192)
**Author:** [@EmirhanAltinok](https://forum.itascainternational.com/u/EmirhanAltinok)\ **Replies:** 2\ **Last updated:** [August 10, 2025, 7:48pm UTC](https://forum.itascainternational.com/t/short-period-spike-in-psa-from-plastic-hardening-model/2192 "2025-08-10T19:48:35Z")
Hi everyone, I performed a zone test to compare the Plastic Hardening model in FLAC2D with the HS-Small model in Plaxis 2D. To do this, I set up a 1D single-column soil model composed of 5 zones, representing a 5-meter-… --- ## [FLAC3D crashes while running this script](https://forum.itascainternational.com/t/flac3d-crashes-while-running-this-script/2167)
**Author:** [@roozbeh](https://forum.itascainternational.com/u/roozbeh)\ **Replies:** 0\ **Last updated:** [July 15, 2025, 8:30pm UTC](https://forum.itascainternational.com/t/flac3d-crashes-while-running-this-script/2167 "2025-07-15T20:30:44Z")
Hi The goal of this model is to calculate settlement resulting from water table drawdown. I based it on the “One-Dimensional Consolidation Considering Secondary Compression” example from the manual, with a simple modifi… --- ## [Simulating tunnel in landslide](https://forum.itascainternational.com/t/simulating-tunnel-in-landslide/2019)
**Author:** [@PietroF](https://forum.itascainternational.com/u/PietroF)\ **Replies:** 4\ **Last updated:** [June 5, 2025, 3:41pm UTC](https://forum.itascainternational.com/t/simulating-tunnel-in-landslide/2019 "2025-06-05T15:41:01Z")
Hi everyone! I have modeled a landslide in FLAC3D. I am trying to reproduce the stress state in a small portion (a box) of the landslide body, inside which a tunnel is located, in order to deepen the analysis on the con… --- ## [Strange PSA Amplification in FLAC Plastic Hardening vs Plaxis HS-Small in 1D Model](https://forum.itascainternational.com/t/strange-psa-amplification-in-flac-plastic-hardening-vs-plaxis-hs-small-in-1d-model/2128)
**Author:** [@EmirhanAltinok](https://forum.itascainternational.com/u/EmirhanAltinok)\ **Replies:** 3\ **Last updated:** [June 18, 2025, 3:08pm UTC](https://forum.itascainternational.com/t/strange-psa-amplification-in-flac-plastic-hardening-vs-plaxis-hs-small-in-1d-model/2128 "2025-06-18T15:08:01Z")
Hi all, I’m running a 1D site response analysis consisting of 8 horizontal layers. The top 7 layers are modeled using PM4Sand and PM4Silt, and the bottom layer (Layer 8) uses the Plastic Hardening (PH) model in FLAC2D, … --- ## [Plastic-Hardening model: Internal parameter calculation fails (small-strain active)](https://forum.itascainternational.com/t/plastic-hardening-model-internal-parameter-calculation-fails-small-strain-active/2110)
**Author:** [@EmirhanAltinok](https://forum.itascainternational.com/u/EmirhanAltinok)\ **Replies:** 2\ **Last updated:** [June 4, 2025, 6:30pm UTC](https://forum.itascainternational.com/t/plastic-hardening-model-internal-parameter-calculation-fails-small-strain-active/2110 "2025-06-04T18:30:28Z")
Hi all, I’m currently using FLAC2D v9 to implement the Plastic-Hardening constitutive model with small-strain stiffness activated. However, I consistently receive the following error : \*\*\* Plastic-Hardening model: Inter… --- ## [Rainfall on slope](https://forum.itascainternational.com/t/rainfall-on-slope/2090)
**Author:** [@Nitesh](https://forum.itascainternational.com/u/Nitesh)\ **Replies:** 3\ **Last updated:** [May 21, 2025, 5:15pm UTC](https://forum.itascainternational.com/t/rainfall-on-slope/2090 "2025-05-21T17:15:24Z")
hey guys, i want to obtain pwp contour from net discharge. i have never done this before . i am unable to give van genuchten model. in flac 3d 9.0. if enyone can give the script of example below for version 9.0. it is he… --- ## [Optimize Substep values](https://forum.itascainternational.com/t/optimize-substep-values/1995)
**Author:** [@sowmyaramanis](https://forum.itascainternational.com/u/sowmyaramanis)\ **Replies:** 1\ **Last updated:** [April 15, 2025, 7:54pm UTC](https://forum.itascainternational.com/t/optimize-substep-values/1995 "2025-04-15T19:54:05Z")
In consolidation analysis, how to choose the substep values for mech and fluid? --- ## [Is there a way to easily vizualize variable boundary conditions in FLAC3D](https://forum.itascainternational.com/t/is-there-a-way-to-easily-vizualize-variable-boundary-conditions-in-flac3d/1986)
**Author:** [@stephaneBeaussier](https://forum.itascainternational.com/u/stephaneBeaussier)\ **Replies:** 1\ **Last updated:** [March 12, 2025, 12:49pm UTC](https://forum.itascainternational.com/t/is-there-a-way-to-easily-vizualize-variable-boundary-conditions-in-flac3d/1986 "2025-03-12T12:49:03Z")
I am apply variable boundary conditions in space. For instance a stress-normal that increase with depth such as the following command: zone face apply stress-normal 0 gradient (0, 0, -1.2e4) Is there a way to easily vi… --- ## [P2Psand undrained hollow cylinder cyclic torsional test](https://forum.itascainternational.com/t/p2psand-undrained-hollow-cylinder-cyclic-torsional-test/1970)
**Author:** [@abarrero](https://forum.itascainternational.com/u/abarrero)\ **Replies:** 2\ **Last updated:** [March 6, 2025, 4:55pm UTC](https://forum.itascainternational.com/t/p2psand-undrained-hollow-cylinder-cyclic-torsional-test/1970 "2025-03-06T16:55:15Z")
Hi FLAC 3D, I’m attempting to replicate the results of Cheng and Detournay (2021) on undrained hollow cylinder cyclic torsional tests on Toyoura Sand, with a relative density $\\D\_r=48%$ and an effective confining pressu… --- ## [Question about timestep solver option for creep problem](https://forum.itascainternational.com/t/question-about-timestep-solver-option-for-creep-problem/1952)
**Author:** [@stephaneBeaussier](https://forum.itascainternational.com/u/stephaneBeaussier)\ **Replies:** 3\ **Last updated:** [February 21, 2025, 10:22am UTC](https://forum.itascainternational.com/t/question-about-timestep-solver-option-for-creep-problem/1952 "2025-02-21T10:22:29Z")
Hi, I am running a model in FLAC3D with the power law creep. I have large strain on and I am running it over a fairly large time total. I configured the maximum and minimum timestep to have automatic adaptation of time… --- ## [Plotting Gridpoint Groups](https://forum.itascainternational.com/t/plotting-gridpoint-groups/1862)
**Author:** [@ddegagne](https://forum.itascainternational.com/u/ddegagne)\ **Replies:** 0\ **Last updated:** [December 19, 2024, 5:39pm UTC](https://forum.itascainternational.com/t/plotting-gridpoint-groups/1862 "2024-12-19T17:39:45Z")
In FLAC3D and FLAC2D you can plot contours of gridpoint data (e.g. displacement) and zone groups, however there is currently no built-in way to show gridpoint labels (e.g. groups). However, you can do this by creating an…