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FLAC2D is a 2D version of Itasca’s FLAC3D numerical modelling software and replaces Itasca's seminal software — FLAC.

With a completely new user interface (UI) and new interactive tools to construct models and interpret result, FLAC2D is their easiest-to-use software. FLAC2D is the best solution to solve complex geotechnical problems for two-dimensional analyses of soil, rock, concrete, structural ground support, and groundwater flow.

Options can be added to expand analyses (dynamic, creep, and thermal) and to create user-defined constitutive models (UDMs). FLAC2D provides an incredibly accurate simulation of real-world geotechnical conditions for engineering applications, such as slope stability, underground excavation behaviour, and earthquake simulations. Flexible commands and scripting allow for model parameterization, flexibility, customization, and automation.

With FLAC2D, the only modelling limitation is your imagination.

Why Choose FLAC2D?


  • Interactively create models from CAD files (DXF, STL), geometry sketching, or images
  • Automatic structured and unstructured mesh generation
  • Skinning to automatically identify model boundaries to set boundary conditions
  • Interactively assign groups, constitutive models, and properties/distributions
  • Built-in database to save/import/export material properties
  • Automatic stress initialization
  • Intuitive commands are easy to learn
  • Most UI interactions are automatically translated into commands, which can be saved to a datafile and re-used
  • Built-in help / command auto-complete
  • Advanced built-in text editor makes creating and running models simple
  • With Version 9’s common UI, seamlessly move between programs or easily couple to other licensed (or demo) Itasca software


  • Multi-threaded to utilize the full power of your computer for faster solutions
  • Multi-threaded FISH Lists and Operators to query or modify the model incredibly quickly, even while cycling
  • New Maxwell damping for 10-200x faster performance for dynamic models
  • FLAC2D plane-strain or axisymmetric models run up to 2-5x faster than equivalent FLAC3D models
  • New, faster implicit solvers for fluid flow and thermal calculations


  • Large-strain simulations to capture the full extent of model deformation
  • Mixed and Nodal Mixed Discretization (NMD) for accurate plasticity calculations
  • Includes over 20 built-in constitutive models for soil, rock, and concrete
  • Built-in liquefaction models P2P-Sand and NorSand with PM4Sand, PM4Silt, and UBCSAND liquefaction models coming
  • Advanced plotting tools to understand model results and for working with hundreds of plots on real projects
  • FISH, Itasca’s scripting language, provides you with unparalleled control over, and customization of, the model
  • Built-in Python 3.10 scripting includes SciPy for plotting, NumPy for computing, and Pyside for UI customization
  • Statistical generation tools for Discrete Fracture Networks (DFNs)


  • Highly customizable UI and modelling
  • All licenses permit two instances of FLAC2D to be run on the same computer
  • Store custom model data via “Extra” variables, for nearly all model elements, that can be read, written to, and plotted
  • Import and export any ASCII data format
  • Optional user-defined constitutive models (UDM) can be written in C++ using Visual Studio template


  • Plane-strain
  • Axisymmetric
  • Static stability
  • Dynamic (option) stability
  • Automatic factor of safety analysis (shear strength reduction method)
  • Back-analyse failure and calibrate forward-prediction
  • Service limit state (SLS) and ultimate limit states (ULS) based on displacements
  • Zone relaxation simulates gradual excavation for construction sequencing, , including out-of-plane excavation
  • Simulate material damage, and failure
  • Effective stress using conventional or complex pore pressure distributions
  • Fluid flow (single-phase)
  • Seepage and consolidation
  • Model ground support correctly with coupled ground-structure interaction (beams, cables, piles/rockbolts, and liners are available)
  • Simulate discontinuities (faults, joints, bedding planes, and construction boundaries) using interfaces; capture yielding or failure, shear displacements, opening, and closure along them
  • Static liquefaction
  • Dynamic (option) liquefaction


Options in FLAC2D are sold separately from the base licence, allowing users to extend the program’s capabilities as meets their own analysis needs while minimizing costs for features that aren't needed. Modules available as options for FLAC2D include: Dynamic, Creep, Thermal, and C++ Plug-ins for creating and running custom user-defined constitutive models (UDMs) and functions.


Further Information

Further information on FLAC2D  is available on the Itasca website including tutorialsfeatures, and transitioning from FLAC. You can also try the FLAC2D Demo or request a quotation here.

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