FLAC3D 6.0
	FLAC3D Modeling
	(an excerpt from FLAC3D Help)

© 2017 Itasca Consulting Group, Inc.

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First Edition (FLAC3D Version 2.1) April 2002

Second Edition (FLAC3D Version 3.0) September 2005

Third Edition (FLAC3D Version 3.1) December 2006

Fourth Edition (FLAC3D Version 4.0) December 2009

Fifth Edition (FLAC3D Version 5.0) October 2012

Sixth Edition (FLAC3D Version 6.0) April 2017

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Precis

This document is a reproduction of the section “FLAC3D Modeling” from the FLAC3D Help. It is provided as a convenience to FLAC3D users who would prefer access to the documentation in a printable form.

There is no substantial difference between the content presented here and that which appears in the FLAC3D Help. In cases of variance, the difference is either a change made to accommodate format in going from a screen-based media to one intended for paper, or, since the Help is updated concurrent to code revisions, that the Help file content is more up-to-date than this document. In any case of variance between the two, precedence should always be given to the Help.

Printing Tip

This document uses a facing pages layout. Users who wish to print the document are advised that printing double-sided, if possible, will produce the best result. A double-sided copy can be bound or inserted into a ring-binder for ease of use.

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This Document and Help Hyperlinks

The FLAC3D Help, from which this document is excerpted and produced, has many cross-reference hyperlinks. These are not reproduced here. Elements in the body-text of the Help that are hyperlinks are colored dark green in this document. This convention has been adopted to allow for link identification within the text of this PDF. To see the matter referenced, however, readers will need to access the equivalent link in the Help file.

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FLAC3D Modeling: Table of Contents

INTRODUCTION … ##

     Overview … ##

          Why A Command-Driven Interface? … ##

          Why FISH? … ##

          The Lagrangian Finite Volume Grid … ##

          Nomenclature … ##

     FLAC3D Features … ##

          Features … ##

          Optional Features … ##

          Modeling Physical Processes and Interactions … ##

          New Features in Version 6.0 … ##

     Comparison with Other Methods … ##

     Fields of Application … ##

     Modeling in Concept … ##

          Numerical Analysis, Geotechnical Engineering … ##

          Modeling Methodology … ##

          General Solution Procedure Illustrated … ##

          The Solution Procedure as a FLAC3D Project … ##

About FLAC3D Commands … ##

     Command Scope & Overwriting … ##

     Targeting Commands with Ranges and Groups … ##

     Command Tools … ##

     Syntax Changes from Version 5.0 to 6.0 … ##

FLAC3D Program Layout … ##

     Files … ##

     FLAC3D Projects Introduced … ##

Guide to the FLAC3D Help File … ##

     User Support … ##

About Itasca Consulting Group Inc …. ##

TUTORIALS … ##

     Tutorial: Quick Start … ##

     Tutorial: Illustrative Model — Mechanics of Using FLAC3D … ##

          Create a New Project … ##

               Discussion … ##

               Projects: In the Interface … ##

          Generate the Grid … ##

               Discussion … ##

               Further Discussion: Meshing With Primitives … ##

               Meshing: In the Interface … ##

          Create Model Groups … ##

               Discussion … ##

               Further Discussion: Model Groups … ##

               Grouping: In the Interface … ##

          Specifying Models, Boundaries, and Initial Conditions … ##

               Discussion … ##

               Further Discussion: Assigning a Constitutive Model … ##

               Further Discussion: Applying Boundary Conditions … ##

               Further Discussion: Specifying Initial Conditions … ##

          Step to Equilibrium … ##

               Discussion … ##

               Further Discussion: Step to Equilibrium … ##

               Stepping: In the Interface … ##

          Alter Model: Excavation … ##

               Discussion … ##

               Further Discussion: Performing Alterations … ##

          Examine Model: Plotting … ##

               Discussion … ##

               Plotting: In the Interface … ##

          Further Alterations: Support … ##

               Discussion … ##

               Further Discussion: Using Save/Restore and Staged Modeling … ##

          Project Finishing … ##

               Discussion … ##

               Finishing: In the Interface … ##

     Tutorial: Working with FISH … ##

          Defining a FISH Function … ##

          Variables … ##

          Using FISH for Custom Calculations … ##

          FISH Rules, Syntax, and Statements, Illustrated … ##

          Arrays and Maps … ##

          Further Information … ##

PROBLEM SOLVING WITH FLAC3D … ##

     Approach and Project Setup … ##

          Modeling on a Spectrum … ##

          Recommended Steps … ##

          Start a Project … ##

     Grid Generation … ##

          Primitive-Based Grids … ##

               Overview of the Grid Primitives … ##

               Connecting Adjoining Primitive Shapes … ##

               Fitting the Grid to Simple Shapes … ##

               Grid Generation with FISH … ##

          Extrusion-Based Grids … ##

               Create a Set … ##

               Define the 2D Geometry … ##

               Zoning and Other Operations … ##

               Define the Extrusion … ##

          Building Blocks-Based Grids … ##

               Create a Building Blocks Set … ##

               Snap Blocks Together … ##

               Refinement Operations and Utilities … ##

               Zoning … ##

          Grids from Outside FLAC3D … ##

               Grids from Rhino/Griddle … ##

          Grid Generation: Additional Facilities … ##

               Densifying Grids … ##

               Geometry-Based Densification: Octree Meshing … ##

               Surface Topography and Layering … ##

     Identifying Regions of the Model … ##

          Groups and Slots … ##

          Using the Group Range Element … ##

          Select and Hide … ##

          Using the Model Pane … ##

               Objects in the Model Pane … ##

               Visualizing Objects … ##

               Selection … ##

               Groups … ##

               Additional Commands … ##

     Working with Geometric Data … ##

          Geometric Data … ##

          Geometry Visualization … ##

          Geometry Painting … ##

          Geometric Filtering - Geometry Range Elements … ##

          Geometry Data and Group Assignment … ##

     Choice of Constitutive Model … ##

          Overview of Constitutive Models … ##

          The Constitutive Models in FLAC3D … ##

          Selection of an Appropriate Model … ##

          The Effect of Water … ##

          Ways to Implement Constitutive Models … ##

     Material Properties … ##

          Intrinsic Deformability Properties … ##

          Intrinsic Strength Properties … ##

          Post-Failure Properties … ##

          Extrapolation to Field-Scale Properties … ##

          Spatial Variation and Randomness of Property Distribution … ##

     Boundary Conditions … ##

          Stress Boundary … ##

               Applied Stress Gradients … ##

               Changing Boundary Stress … ##

               Cautions and Advice … ##

          Displacement Boundary … ##

               Local System and Applied Velocities … ##

               Surface Corners and Velocity Boundaries … ##

               Fix vs. Apply … ##

               Reaction Forces … ##

               Nonuniform Velocities … ##

          Real Boundaries — Choosing the Right Type … ##

          Artificial Boundaries … ##

               Symmetry Planes … ##

               Boundary Truncation … ##

     Initial Conditions … ##

          Uniform Stresses — No Gravity … ##

          Stresses with Gradients — Uniform Material … ##

          Stresses with Gradients — Nonuniform Material … ##

          Stress Initialization in a Nonuniform Material … ##

          Compaction within a Nonuniform Grid … ##

          Initial Stresses following a Model Change … ##

          Stress and Pore-Pressure Initialization with a Phreatic Surface … ##

          Initialization of Velocities … ##

     Reaching Equilibrium … ##

          Convergence Criteria … ##

               Maximum Out-of-Balance Force … ##

               Local Maximum Force Ratio … ##

               Average Force Ratio … ##

               Maximum Force Ratio … ##

               Ratio … ##

               Convergence … ##

          Choosing Convergence Criteria … ##

          Evaluating Equilibrium … ##

               Effects of Large Stiffness Differences … ##

     Loading and Sequential Modeling … ##

          Example: Loading on Three Tunnels … ##

     Structural Support … ##

     Interfaces … ##

     Tips and Advice … ##

          1. Check Model Runtime … ##

          2. Effects on Runtime … ##

          3. Considerations for Zoning Density … ##

          4. Automatic Detection of an Equilibrium State … ##

          5. Considerations for Selecting Damping … ##

          6. Check Model Response … ##

          7. Initializing Variables … ##

          8. Minimizing Transient Effects on Static Analysis … ##

          9. Changing Material Models … ##

          10. Running Problems with In-Situ Field Stresses and Gravity … ##

          11. Determining Collapse Loads … ##

          12. Determining Factor of Safety … ##

          13. Use Bulk and Shear Moduli … ##

          FLAC3D Runtime Benchmark … ##

     Interpretation … ##

          Unbalanced Force and Convergence … ##

          Gridpoint Velocities … ##

          Plastic Indicators … ##

          Histories … ##

          Endnote … ##

     Project Completion … ##

     References … ##