# FLAC2D **URL:** https://forum.itascainternational.com/c/flac2d/23.md [Latest](https://forum.itascainternational.com/latest.md) · [Categories](https://forum.itascainternational.com/categories.md) · [Tags](https://forum.itascainternational.com/tags.md) --- ## [About the FLAC2D category](https://forum.itascainternational.com/t/about-the-flac2d-category/810)
**Author:** [@jwang](https://forum.itascainternational.com/u/jwang)\ **Replies:** 0
FLAC2D is a 2D version of Itasca’s FLAC3D numerical modeling software. With a completely new user interface (UI) and new interactive tools to construct models and interpret result, FLAC2D is our easiest-to-use software. F… --- ## [Dynamic Effective Stress Analysis (PM4Sand/PM4Silt) : Interpreting Large-Strain Collapse vs. Large-Strain Off Displacements](https://forum.itascainternational.com/t/dynamic-effective-stress-analysis-pm4sand-pm4silt-interpreting-large-strain-collapse-vs-large-strain-off-displacements/2412)
**Author:** [@stmicheljerome](https://forum.itascainternational.com/u/stmicheljerome)\ **Replies:** 3\ **Last updated:** [October 12, 2026, 6:20pm UTC](https://forum.itascainternational.com/t/dynamic-effective-stress-analysis-pm4sand-pm4silt-interpreting-large-strain-collapse-vs-large-strain-off-displacements/2412 "2026-10-12T18:20:24Z")
Hi everyone, I am currently running a dynamic effective stress analysis on a embankment dam model using FLAC2D, utilizing PM4Sand and PM4Silt constitutive models for the liquefiable/sensitive foundation and deposit laye… --- ## [Crash When Applying Maxwell Damping to Liner Elements in Dynamic Analysis](https://forum.itascainternational.com/t/crash-when-applying-maxwell-damping-to-liner-elements-in-dynamic-analysis/2415)
**Author:** [@BZH](https://forum.itascainternational.com/u/BZH)\ **Replies:** 3\ **Last updated:** [September 30, 2026, 2:13pm UTC](https://forum.itascainternational.com/t/crash-when-applying-maxwell-damping-to-liner-elements-in-dynamic-analysis/2415 "2026-09-30T14:13:27Z")
I’m modifying the Embedded Retaining Wall (FLAC2D) example and added Maxwell damping to the liner elements for a dynamic analysis using: structure dynamic damping maxwell 0.0385 0.5 0.0335 3.5 0.052 25.0 I’ve attached … --- ## [Azure Performance](https://forum.itascainternational.com/t/azure-performance/2414)
**Author:** [@loneshark26](https://forum.itascainternational.com/u/loneshark26)\ **Replies:** 0\ **Last updated:** [September 22, 2026, 1:35pm UTC](https://forum.itascainternational.com/t/azure-performance/2414 "2026-09-22T13:35:06Z")
Just curious if anyone else has successfully configured FLAC2D into Azure compute, and if so, what SKU / CPU combo did you end up deploying? We found the F-series with AMD CPU to be the fastest when doing testing. --- ## [Modeling Centrifuge Test with Attached Boundary Conditions in FLAC](https://forum.itascainternational.com/t/modeling-centrifuge-test-with-attached-boundary-conditions-in-flac/1779)
**Author:** [@EmirhanAltinok](https://forum.itascainternational.com/u/EmirhanAltinok)\ **Replies:** 4\ **Last updated:** [June 11, 2026, 9:05pm UTC](https://forum.itascainternational.com/t/modeling-centrifuge-test-with-attached-boundary-conditions-in-flac/1779 "2026-06-11T21:05:35Z")
Hello Everyone, I am currently working on modeling a centrifuge test at prototype scale. My geometry includes three liquefiable sand layers with varying relative densities (Dr), so I am using the PM4Sand model. The expe… --- ## [Maxwell Damping in Nonlinear Dynamic Analysis](https://forum.itascainternational.com/t/maxwell-damping-in-nonlinear-dynamic-analysis/2357)
**Author:** [@Miguel\_S](https://forum.itascainternational.com/u/Miguel_S)\ **Replies:** 2\ **Last updated:** [March 26, 2026, 2:46am UTC](https://forum.itascainternational.com/t/maxwell-damping-in-nonlinear-dynamic-analysis/2357 "2026-03-26T02:46:32Z")
I have performed a dynamic analysis of an earth structure. Previously, I ran the model using Rayleigh damping (zone dynamic damping rayleigh 0.005 1.0) without encountering any issues during the simulation. However, whe… --- ## [Exporting Deformed Mesh](https://forum.itascainternational.com/t/exporting-deformed-mesh/2354)
**Author:** [@asabet](https://forum.itascainternational.com/u/asabet)\ **Replies:** 2\ **Last updated:** [March 24, 2026, 6:18pm UTC](https://forum.itascainternational.com/t/exporting-deformed-mesh/2354 "2026-03-24T18:18:59Z")
Is there a way to export the position of the deformed gridpoints without having to manually calculate it from displacements? --- ## [Mismatch of Displacement Input in Dynamic Analysis](https://forum.itascainternational.com/t/mismatch-of-displacement-input-in-dynamic-analysis/1820)
**Author:** [@JonathasBB](https://forum.itascainternational.com/u/JonathasBB)\ **Replies:** 10\ **Last updated:** [January 26, 2026, 5:03am UTC](https://forum.itascainternational.com/t/mismatch-of-displacement-input-in-dynamic-analysis/1820 "2026-01-26T05:03:17Z")
Hi Everyone and @itascan. I am currently working on modeling a dynamic analysis of a tailings dam. I am performing some verifications to validate the model, and one of them is to verify if the input ground motion matche… --- ## [Water Table Setting in FLAC2D 8.1](https://forum.itascainternational.com/t/water-table-setting-in-flac2d-8-1/2298)
**Author:** [@New\_user](https://forum.itascainternational.com/u/New_user)\ **Replies:** 2\ **Last updated:** [December 2, 2025, 5:43pm UTC](https://forum.itascainternational.com/t/water-table-setting-in-flac2d-8-1/2298 "2025-12-02T17:43:18Z")
How can I define a fixed groundwater table for an embankment slope in FLAC2D 8.1? --- ## [Cnnverting group command from FLAC2D v8 to v9](https://forum.itascainternational.com/t/cnnverting-group-command-from-flac2d-v8-to-v9/2297)
**Author:** [@AdamL](https://forum.itascainternational.com/u/AdamL)\ **Replies:** 1\ **Last updated:** [December 2, 2025, 2:54pm UTC](https://forum.itascainternational.com/t/cnnverting-group-command-from-flac2d-v8-to-v9/2297 "2025-12-02T14:54:25Z")
Morning all, I’m trying to convert a file form v8 to v9 and I’m getting stuck with the group command. The v8 command is group ‘L1-1’ notnull region tab 5 Where the table is 4 to 6 grid points, creating a polygon that… --- ## [Structure Python API of FLAC2D](https://forum.itascainternational.com/t/structure-python-api-of-flac2d/1117)
**Author:** [@Sullivan](https://forum.itascainternational.com/u/Sullivan)\ **Replies:** 5\ **Last updated:** [September 11, 2025, 1:16am UTC](https://forum.itascainternational.com/t/structure-python-api-of-flac2d/1117 "2025-09-11T01:16:39Z")
Hi, Will structure element python api be included in FLAC2D in the near future? --- ## [The distribution load in Beam model](https://forum.itascainternational.com/t/the-distribution-load-in-beam-model/2208)
**Author:** [@Sullivan](https://forum.itascainternational.com/u/Sullivan)\ **Replies:** 2\ **Last updated:** [August 19, 2025, 12:40am UTC](https://forum.itascainternational.com/t/the-distribution-load-in-beam-model/2208 "2025-08-19T00:40:43Z")
My flac2d version is 9.0.181. I find that the structure of beam should not be applied a non-uniformly distribution load, so how can I apply the load? --- ## [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… --- ## [Plotting of variables through f2grid file](https://forum.itascainternational.com/t/plotting-of-variables-through-f2grid-file/2102)
**Author:** [@katerinaziot](https://forum.itascainternational.com/u/katerinaziot)\ **Replies:** 4\ **Last updated:** [May 28, 2025, 4:48am UTC](https://forum.itascainternational.com/t/plotting-of-variables-through-f2grid-file/2102 "2025-05-28T04:48:32Z")
Hello peeps. I’m probably missing something simple here, but I could use a hand figuring this out. I want to export grid properties and contents for post-processing and overall “beautification” of plots with python late… --- ## [Water table variation in FLAC](https://forum.itascainternational.com/t/water-table-variation-in-flac/1974)
**Author:** [@agapanto](https://forum.itascainternational.com/u/agapanto)\ **Replies:** 3\ **Last updated:** [March 7, 2025, 4:40pm UTC](https://forum.itascainternational.com/t/water-table-variation-in-flac/1974 "2025-03-07T16:40:01Z")
Hi all, I’m using a water table in my FLAC v.8 model with the command water table. I need to change the water table level, by lowering it from a level L1 to a level L2. The Command Reference section of the FLAC manual … --- ## [Pore Pressure Generation in Axisymmetry Model](https://forum.itascainternational.com/t/pore-pressure-generation-in-axisymmetry-model/1651)
**Author:** [@CrissBidermann](https://forum.itascainternational.com/u/CrissBidermann)\ **Replies:** 5\ **Last updated:** [December 20, 2024, 11:11pm UTC](https://forum.itascainternational.com/t/pore-pressure-generation-in-axisymmetry-model/1651 "2024-12-20T23:11:47Z")
Is it possible to generate pore pressures in an axisymmetric model? I am running an undrained triaxial test code, and I am unable to generate pore pressures in the model if the command “model configure axisymmetry” is en… --- ## [Total Strain Increment in FLAC2D](https://forum.itascainternational.com/t/total-strain-increment-in-flac2d/1710)
**Author:** [@SamVarun10](https://forum.itascainternational.com/u/SamVarun10)\ **Replies:** 1\ **Last updated:** [September 23, 2024, 6:03pm UTC](https://forum.itascainternational.com/t/total-strain-increment-in-flac2d/1710 "2024-09-23T18:03:33Z")
Hello everyone, I want to ask what does the quantity tsi and tsr convey in FLAC2D is. Currently, I am using the version 8.0, and this is the contour option for tsi and tsr. I cannot create a plot or history for tsi and … --- ## [NorSand Model Operation in FLAC2D/FLAC3D](https://forum.itascainternational.com/t/norsand-model-operation-in-flac2d-flac3d/1660)
**Author:** [@CrissBidermann](https://forum.itascainternational.com/u/CrissBidermann)\ **Replies:** 2\ **Last updated:** [August 30, 2024, 12:48pm UTC](https://forum.itascainternational.com/t/norsand-model-operation-in-flac2d-flac3d/1660 "2024-08-30T12:48:19Z")
I have heard from several sources that the NorSand model performs better in Plaxis than in FLAC, in terms of deformation models, for example in static analysis of tailings deposits. This is due to the FLAC solution proce… --- ## [Zone property values not updating correctly?](https://forum.itascainternational.com/t/zone-property-values-not-updating-correctly/1612)
**Author:** [@AdamL](https://forum.itascainternational.com/u/AdamL)\ **Replies:** 3\ **Last updated:** [August 30, 2024, 10:11am UTC](https://forum.itascainternational.com/t/zone-property-values-not-updating-correctly/1612 "2024-08-30T10:11:37Z")
I’m currently trying to assign shear-normal values based on a function for each zone, with the function based on vertical stress values. The result looks correct, but as a sanity check, I plotted the zone property shear-… --- ## [C++ UDM Output in FLAC](https://forum.itascainternational.com/t/c-udm-output-in-flac/1571)
**Author:** [@SamVarun10](https://forum.itascainternational.com/u/SamVarun10)\ **Replies:** 4\ **Last updated:** [August 5, 2024, 2:33pm UTC](https://forum.itascainternational.com/t/c-udm-output-in-flac/1571 "2024-08-05T14:33:45Z")
Hello all, I have modified “FLAC Constitutive Model” into a simple strain softening model and tried to run a basic UCS Test using this constitutive model. For the basic understand of what is happening inside, I create… --- ## [FLAC2D custom contour plot?](https://forum.itascainternational.com/t/flac2d-custom-contour-plot/1607)
**Author:** [@AdamL](https://forum.itascainternational.com/u/AdamL)\ **Replies:** 2\ **Last updated:** [August 1, 2024, 4:14pm UTC](https://forum.itascainternational.com/t/flac2d-custom-contour-plot/1607 "2024-08-01T16:14:07Z")
Hi All, A quick question: Is it possible to create a custom contour plot? And if so, how/where do I do it? I’m currently working through FISH tutorials, but I’ve yet to see an example of how it is done. I’m trying to g… --- ## [Cable elements as soil Anchors](https://forum.itascainternational.com/t/cable-elements-as-soil-anchors/1551)
**Author:** [@Razi](https://forum.itascainternational.com/u/Razi)\ **Replies:** 5\ **Last updated:** [July 22, 2024, 2:46pm UTC](https://forum.itascainternational.com/t/cable-elements-as-soil-anchors/1551 "2024-07-22T14:46:55Z")
Hi all, when i model anchors i need to define tension at the free length. seems the tension is not the define locking load (as in plaxis/wallap),but the total response of the model to applied force. at the end the axia… --- ## [How to initialize moment and displacement in beam struct element?](https://forum.itascainternational.com/t/how-to-initialize-moment-and-displacement-in-beam-struct-element/1550)
**Author:** [@Razi](https://forum.itascainternational.com/u/Razi)\ **Replies:** 4\ **Last updated:** [July 21, 2024, 6:08am UTC](https://forum.itascainternational.com/t/how-to-initialize-moment-and-displacement-in-beam-struct-element/1550 "2024-07-21T06:08:37Z")
How to initialize moment and displacement in beam struct element ? --- ## [Command corr ffrot in FLAC2D/3D](https://forum.itascainternational.com/t/command-corr-ffrot-in-flac2d-3d/1404)
**Author:** [@CrissBidermann](https://forum.itascainternational.com/u/CrissBidermann)\ **Replies:** 3\ **Last updated:** [June 11, 2024, 5:14pm UTC](https://forum.itascainternational.com/t/command-corr-ffrot-in-flac2d-3d/1404 "2024-06-11T17:14:54Z")
In FLAC 8.1 there was the “corr ffrot” command that allowed adjusting the reaction forces resulting from free field conditions to prevent the model from experiencing rotation. Why is there no equivalent of this command f… --- ## [Liner element - Element system](https://forum.itascainternational.com/t/liner-element-element-system/1489)
**Author:** [@AgustinMG](https://forum.itascainternational.com/u/AgustinMG)\ **Replies:** 1\ **Last updated:** [June 4, 2024, 8:09pm UTC](https://forum.itascainternational.com/t/liner-element-element-system/1489 "2024-06-04T20:09:31Z")
Hi everyone, I have performed a 2D model of an excavation with a lining that has been modeled as a “liner” element. The results of the liner that interest me are the axial stress, shear stress and bending moment. When … --- ## [Query while using print command in FLAC2D](https://forum.itascainternational.com/t/query-while-using-print-command-in-flac2d/1468)
**Author:** [@SamVarun10](https://forum.itascainternational.com/u/SamVarun10)\ **Replies:** 7\ **Last updated:** [May 23, 2024, 7:16am UTC](https://forum.itascainternational.com/t/query-while-using-print-command-in-flac2d/1468 "2024-05-23T07:16:31Z")
Hello all, In the C++ code of Strain softening, the following are the variables which are initialised: Here, the initial variables namely: Bulk Mod, Shear Mod, Young’s Mod, Poisson, Cohesion, Friction, Dilation,Tens… --- ## [Defining a new array in User-Defined Constitutive Model](https://forum.itascainternational.com/t/defining-a-new-array-in-user-defined-constitutive-model/1451)
**Author:** [@SamVarun10](https://forum.itascainternational.com/u/SamVarun10)\ **Replies:** 1\ **Last updated:** [May 12, 2024, 1:38pm UTC](https://forum.itascainternational.com/t/defining-a-new-array-in-user-defined-constitutive-model/1451 "2024-05-12T13:38:50Z")
Hello, Is there any way to create an array of some size using cppudm module and print in in FLAC? I tried adding Double test\_\[5\]; in Header file & Modelexample::Modelexample() : bulk\_(0.0), shear\_(0.0), cohesion\_(0.… --- ## [ini\_PH fish command](https://forum.itascainternational.com/t/ini-ph-fish-command/1435)
**Author:** [@Razi](https://forum.itascainternational.com/u/Razi)\ **Replies:** 1\ **Last updated:** [May 6, 2024, 2:04pm UTC](https://forum.itascainternational.com/t/ini-ph-fish-command/1435 "2024-05-06T14:04:20Z")
Hi, I use FLAC2D. I can’t find “initial\_PH” fish in my library. is it goes only with FLAC3D? any alternatives? TNX, Razi --- ## [FISH fcns on pile elements: struct.pile.stress.confining](https://forum.itascainternational.com/t/fish-fcns-on-pile-elements-struct-pile-stress-confining/1418)
**Author:** [@katerinaziot](https://forum.itascainternational.com/u/katerinaziot)\ **Replies:** 6\ **Last updated:** [April 30, 2024, 5:26pm UTC](https://forum.itascainternational.com/t/fish-fcns-on-pile-elements-struct-pile-stress-confining/1418 "2024-04-30T17:26:18Z")
Greetings community - I’m playing around with pile elements in FLAC2D. Building on an example provided in the documentation but not in the prjs of the installed software. I want to be able to fetch the confining stress … --- ## [Printing of new values using User-Defined Constitutive Model](https://forum.itascainternational.com/t/printing-of-new-values-using-user-defined-constitutive-model/1427)
**Author:** [@SamVarun10](https://forum.itascainternational.com/u/SamVarun10)\ **Replies:** 1\ **Last updated:** [April 29, 2024, 1:27pm UTC](https://forum.itascainternational.com/t/printing-of-new-values-using-user-defined-constitutive-model/1427 "2024-04-29T13:27:40Z")
Hello everyone, I need to ask about cpp file of e.g. Strain Softening Model. Is there a way in which I can use things like std::cout etc. to print some values in FLAC? Is there some way to do this for each step/zone? … [Next page](https://forum.itascainternational.com/c/flac2d/23.md?page=1)