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Continuum Modeling for Geomechanics in 2D

Choose FLAC2D for advanced geotechnical problem solving. Ideal for 2D soil, rock, concrete analysis, structural ground support, and groundwater flow. Optimize solutions now and check out the latest version, FLAC2D 9.1!


What Kinds Of Problems Can FLAC2D Solve?

A wharf built into a slope is composed of beam and pile structural elements. Max shear strain incremental contours and horizontal displacement of wharf are shown after being subjected to an earthquake.

Concrete diaphragm wall model showing horizontal displacement contours, total displacement vectors, bending moments and horizontal displacement along liner, plus bending moment in support struts.

Elliptical supported tunnel developed in a series of excavation and support sequences.

Automatic factor of safety contours for a mine slope.

Top: Mine tailings dam constructed in stages. Bottom: Max shear strain increments after an earthquake.

Post-peak strength behavior of a mine pillar without surrounding backfill.


Why Choose FLAC2D?

Explore FLAC2D's comprehensive features and user-friendly interface. Unlock powerful computing capabilities, including the ability to run two instances simultaneously. Discover why FLAC2D is the ideal choice:
  • Plane strain

  • Axisymmetric (mechanical)

  • Small-strain mechanics (gridpoints remain fixed)

  • Large-strain mechanics (gridpoints move with displacement)

  • Effective stress (pore pressure)

  • Automatic factor of safety

  • Back-analyze failure and calibrate forward-prediction

  • Multiple, simultaneous failure mechanisms

  • Zone relaxation for gradual excavation and construction sequencing and out-of-plane closure

  • Groundwater flow

  • Service limit state (SLS) and ultimate limit states (ULS) based on displacements

  • Liquefaction

  • Settlement and Consolidation

  • Surface Subsidence

  • Recovery and dilution

  • Coupled ground-structure interaction (beams, cables, piles, shells, geotextiles, liners)

  • Options available: Dynamics (Earthquakes, Blasting, Vibration), Thermal, Creep, User-Defined Constitutive Models (UDM)

  • FLAC2D makes model construction easy with interactive tools in Sketch to create the model or import CAD files, automatic meshing, and intuitive boundary skinning. Easily define groups in the Model pane and assign constitutive models and material properties using the built-in user database. Automatic stress initialization based on model topography and user settings greatly simplifies the modeling workflow. A wizard is available to convert FLAC 8.1 grids into a FLAC2D mesh.

  • FLAC2D utilizes multi-threading and optimized solutions for fast, responsive, and accurate simulations. Maxwell damping for dynamic simulations and enhanced solvers for fluid flow and thermal simulations enable efficient solution times.

    Multi-threaded FISH and Python libraries provide extremely efficient model scripting when user customization is chosen. FLAC2D plane-strain or axisymmetric models run up to 5x faster than equivalent 3D models. Users may also run two instances of FLAC2D on the same computer simultaneously, cutting down on overall time to solution for multiple models

  • FLAC2D offers robust simulation capabilities, including large-strain simulation to visualize the full extent of model deformation; 20 built-in constitutive models for soil, rock, concrete, and metal; dynamics analysis to simulate earthquakes and liquefaction; and structural elements to design ground support.

    Advanced plotting tools, FISH scripting, and Python integration provide unparalleled model control and customization, while statistical tools and data import options expand modeling possibilities.

  • Enjoy flexibility in modeling and your workspace with FLAC2D’s highly adaptable tiled user interface that allow users to layout the program as preferred, work with hundreds of plots efficiently, and build, construct, and modify the modeling workflow as needed.

    Use FISH and/or Python scripting for model parameterization, custom visualizations, adding new physics, and/or model run control. Use one of the 20 built-in constitutive models for material behavior or develop a custom user-defined constitutive model (UDM).

  • In conjunction with interactive tools, FLAC2D uses commands to provide a compact representation of the model (as a data file) for repeatability, to ensure path dependency (excavation sequence and any other sequence of events, such as boundary conditions or material properties), and for flexibility.

    Intuitively structured commands, built-in contextual help, and command auto-completion help users learn and work with commands. Most user interface interactions are automatically translated into commands so you can see how they are composed and reuse them. The built-in text editor adds efficiency to creating and running models with commands.

  • Improved Fluid Flow and Thermal Analyses

    The mechanical-fluid and mechanical-thermal commands and workflow have been significantly simplified, improving the usability and learnability of fluid flow analyses.


  • Improved Multi-Process Modeling

    Multi-process models contain two or more coupled or decoupled solutions (mechanical/static, fluid, dynamic, thermal, and creep). Significant improvements have been made to simplify multi-process models, making analyses easier to use and understand.


  • Updated Null Logic

    Zones may be nulled to represent removal of material that you may want to backfill later or cycle through glaciation periods (ice/no ice). When a zone is nulled, the model behaves as if the zone has been deleted, but the zone position and shape continue to be tracked for easy reuse later.


  • Better Scripting

    • Python can now access the built-in geometry logic (user-defined nodes, edges, faces, volumes, etc.).
    • The contourpy Python library (for calculating contours of 2D quadrilateral grids) is now built-in.

  • And More!

    • Grouping operations are now faster.
    • New Hoek-Brown curve fitting and plotting tool – then add these value as PROPERTY commands right into your model.
    • QT 6 user interface libraries have been updated:
    – User interface appearance is improved on high-resolution monitors.
    – No need to specify OpenGL Mode.
    • By place an * at the start of a command, all related warning messages will be suppressed.


Voyez ce que les utilisateurs ont à dire

"Les récentes modifications et améliorations apportées aux codes FLAC2D & 3D de [ITASCA] répondent très bien à nos exigences professionnelles croissantes dans les applications avancées de génie civil - bien joué."
Fulvio Besseghini, Lombardi Engineering Ltd.
"La flexibilité que FLAC[2D] offre pour simuler les systèmes géotechniques de manière aussi réaliste que possible, ainsi que l'accessibilité à presque toutes les fonctionnalités de FLAC grâce à FISH, ont été des points clés qui m'ont motivé à utiliser FLAC dans mes recherches."
Girish Kumar, PhD
"L'interface graphique, le langage FISH, les modèles constitutifs et la formulation font de FLAC mon outil d'analyse privilégié pour les projets et les travaux de recherche."
Richard Armstrong, Geoanalysis Support/ CSU, Sacramento
"Le logiciel FLAC2D me fournit tous les éléments nécessaires pour réaliser une analyse dynamique réussie."
Rita Abou Jaoude, PhD
"FLAC2D et FLAC3D se sont avérés être des outils essentiels dans les domaines de la géomécanique et du génie géotechnique. Ces deux codes représentent un véritable étalon pour réaliser des analyses de stabilité des pentes et résoudre les problèmes d'interaction sol-structure, notamment en ce qui concerne les ponts et viaducs."
Walter Salvatore, Consorzio Fabre
"L'implémentation de la méthode des différences finies garantit des résultats de haute qualité, et les nouvelles versions des codes ont été considérablement améliorées avec une nouvelle interface utilisateur tandis que le support technique d'ITASCA est absolument exceptionnel."
Walter Salvatore, Consorzio Fabre

Expand Your Software Capabilities With These Options:

Expand your FLAC2D software capabilities with our range of add-on options, designed to tackle diverse engineering challenges effectively. Explore our selection of options to customize your FLAC2D experience.

  • FLAC2D offers two-dimensional, fully dynamic analysis that extends simulation capabilities to a wide range of dynamic problems in earthquake engineering, soil liquefaction, seismology, blasting, and mine rockbursts. You can specify acceleration, velocity, or stress waves as an exterior or interior boundary condition and include wave absorbing and free-field boundary conditions.

    Dynamics supports soil-structure interaction, can be coupled to thermal analysis, and includes a Dynamics Wizard to pre-process ground motions. Couple Dynamics to groundwater flow for analyses involving time-dependent pore pressure change associated with liquefaction. FLAC2D includes several dynamic and liquefaction constitutive models and includes Maxwell damping, resulting in fast dynamic model run times.


  • FLAC2D’s thermal analysis combines conduction and advection models to simulate heat transfer and thermal-induced displacements for modeling geothermal and nuclear waste applications. Thermal provides for one-way coupling to the mechanical stress and pore-pressure calculations. It includes four thermal material models and variable boundary conditions.

    Heat sources may be inserted into the model, which may decay exponentially with time. The Hydration-Drucker-Prager constitutive model is also included, which can adjust the mechanical properties of a material corresponding to the hydration grade (or equivalent concrete age). New solvers are now included in FLAC2D, making thermal model run times incredibly fast.


  • FLAC2D’s creep analysis can be used to simulate the behavior of materials that exhibit time-dependent material behavior. FLAC2D provides 10 constitutive models for simulating creep, which cover both viscoelastic and viscoplastic behavior. You can also modify these models or create new creep constitutive models using C++ for a user-defined constitutive model (UDM). Applications include oil and gas reservoirs, compressed-air energy storage, mining, frozen-soils, nuclear waste disposal, and deep tunnels.


  • FLAC2D’s user-defined constitutive model (UDM) greatly expands the software’s versatility by permitting users to develop their own constitutive models, using C++ scripting, to describe a material behavior that differs from ITASCA’s built-in library. Templates and instructions are provided. Start by modifying one of the built-in constitutive models or create an entirely new material behavior.

    UDMs can be automatically loaded into your FLAC2D project and may be freely distributed (as a DLL file). ITASCA maintains a UDM Library on our website should you want to share your constitutive model. With the UDM, you may also download and run constitutive models from the UDM Library, including PM4 and UBC liquefaction models.



Software Support

Our commitment extends beyond excellent products. We offer comprehensive support for all your inquiries. Explore the links below to kick-start your journey:


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