Problem Solving with 3DEC

This section provides guidance in the use of 3DEC in problem solving for rock mechanics engineering. In Approach and Project Setup, an outline of the steps recommended for performing a geomechanics analysis is given, followed in the other sections by an examination of specific aspects that must be considered in any model creation and solution. These include:

• Model Generation

• Zoning 3DEC Blocks

• Choice of Constitutive Model

• Material Properties

• Boundary Conditions

• Initial Conditions

• Reaching Equilibrium

• Loading and Sequential Modeling

• Working with Geometric Data

• Working with FISH

• Exporting 3DEC models

• Approach and Project Setup
  • Modeling on a Spectrum
  • Recommended Steps
  • Start a Project
• Model Generation
  • Blocks, Joints, and Zones
  • Creating Single Blocks
  • Generating Block Assemblies
    • Generating Blocks from Geometry
    • Generating Blocks from VRML
    • Surface Topography and Face Extrusion
    • Voronoi Block Generation
    • Block Import/Export
  • Cutting Blocks
  • Block Generation: Densify and Octree
  • Block Quality Metrics
  • A Note on Tolerance
• Zoning 3DEC Blocks
  • Rigid vs. Deformable
  • Zone Types
  • Generating Zones
  • Importing and Merging
• Choice of Constitutive Model
  • Zones
    • Overview of Constitutive Models
    • Selection of an Appropriate Model
    • The Effect of Water
    • Ways to Implement Constitutive Models
  • Joints
    • Selection of an Appropriate Model
• Material Properties
  • Zone Properties
    • Mass Density
    • Intrinsic Deformability Properties
    • Intrinsic Strength Properties
    • Post-Failure Properties
    • Extrapolation to Field-Scale Properties
    • Spatial Variation and Randomness of Property Distribution
  • Joint Properties
    • Choosing Joint Properties
    • Contact Material Table
    • Joint Persistence
• Boundary Conditions
  • Stress Boundary
    • Applied Stress Gradient
    • Changing Boundary Stresses
    • Checking the Boundary Condition
    • Cautions and Advice
  • Displacement Boundary
  • Real Boundaries – Choosing the Right Type
  • Artificial Boundaries
    • Symmetry Planes
    • Boundary Truncation – Location of the Far-Field Boundary
• Initial Conditions
  • Uniform Stresses in an Unjointed Medium: No Gravity
  • Stresses with Gradients in an Unjointed Medium: Uniform Material
  • Stresses with Gradients in a Nonuniform Material
  • Compaction within a Model with Nonuniform Zoning
  • Initial Stresses following a Model Change
  • Stresses in a Jointed Medium
  • Topographical Stresses
  • Specifying Initial Pore Pressure
  • Transferring Field Stresses to Model Stresses
• Reaching Equilibrium
  • Convergence Criteria
    • Local Maximum Force Ratio
    • Average Force Ratio
    • Maximum Force Ratio
    • Convergence
  • Choosing Convergence Criteria
  • Evaluating Equilibrium
• Loading and Sequential Modeling
• Working with Geometric Data
  • Geometric Data
  • Geometry Visualization
  • Geometry Painting
  • Geometric Filtering - Geometry Range Elements
  • Geometry Data and Group Assignment
  • Geometry Data: Examples
    • Assign Group Names Based on Their Relationship to DXF Files
    • Ignore Existing Groups — Build New Ones Based on Surfaces
    • Partition Existing Groups Based on Surfaces
    • Blocks below Surfaces become Separate Groups, Outside Groups Remain Unchanged
    • Blocks above the Surfaces become a New Group, Everything below is Unchanged
    • Blocks Intersecting Surfaces becomes Separate Groups
    • Split Blocks below Surfaces
    • Split Large Blocks Intersecting Surfaces
• Working with FISH
• Exporting 3DEC models
  • Exporting to FLAC3D
  • Exporting to PFC
  • Exporting to UDEC