当非饱和土力学教材来看
1 Introduction
2 Numerical Modeling: What, Why and How
2.1 Introduction
2.2 What is a numerical model?
2.3 Modeling in geotechnical engineering
2.4 Why model?
Quantitative predictions
Compare alternatives
Identify governing parameters
Discover & understand physical process - train our thinking
2.5 How to model
Make a guess
Simplify geometry
Start simple
Do numerical experiments
Model only essential components
Start with estimated material properties
Interrogate the results
Evaluate results in the context of expected results
Remember the real world
2.6 How not to model
2.7 Closing remarks
3 Geometry and Meshing
3.1 Introduction
3.2 Geometry objects in GeoStudio
Soil regions, points and lines
Free points
Free lines
Interface elements on lines
Circular openings
3.3 Mesh generation
Structured mesh
Unstructured quad and triangle mesh
Unstructured triangular mesh
Triangular grid regions
Rectangular grid of quads
3.4 Surface layers
3.5 Joining regions
3.6 Meshing for transient analyses
3.7 Finite elements
3.8 Element fundamentals
Element nodes
Field variable distribution
Element and mesh compatibility
Numerical integration
Secondary variables
3.9 Infinite regions
3.10 General guidelines for meshing
Number of elements
Effect of drawing scale
Mesh purpose
Simplified geometry
4 Material Models and Properties
4.1 Soil behavior models
Material models in SEEP/W
4.1 Soil water storage – water content function
Factors affecting the volumetric water content
4.2 Storage function types and estimation methods
Estimation method 1 (grain size - Modified Kovacs)
Estimation method 2 (sample functions)
Closed form option 1 (Fredlund and Xing, 1994)
Closed form option 2 (Van Genuchten, 1980)
4.3 Soil material function measurement
Direct measurement of water content function
4.4 Coefficient of volume compressibility ( )
4.5 Hydraulic conductivity
4.6 Frozen ground hydraulic conductivity
4.7 Conductivity function estimation methods
Method 1 (Fredlund et al, 1994)
Method 2 (Green and Corey, 1971)
Method 3 (Van Genuchten, 1980)
4.8 Interface model parameters
4.9 Storativity and transmissivity
4.10 Sensitivity of hydraulic results to material properties
Changes to the air-entry value (AEV)
Changes to the saturated hydraulic conductivity
Changes to the slope of the VWC function
Changes to the residual volumetric water content
5 Boundary Conditions
5.1 Introduction
5.2 Fundamentals
5.3 Boundary condition locations
Region face boundary conditions
5.4 Head boundary conditions
Definition of total head
Head boundary conditions on a dam
Constant pressure conditions
Far field head conditions
5.5 Specified boundary flows
5.6 Sources and sinks
5.7 Seepage faces
5.8 Free drainage (unit gradient)
5.9 Ground surface infiltration and evaporation
5.10 Far field boundary conditions
5.11 Boundary functions
General
Head versus time
Head versus volume
Nodal flux Q versus time
Unit flow rate versus time
Modifier function
6 Analysis Types
6.1 Steady state
Boundary condition types in steady state
6.2 Transient
Initial conditions
Drawing the initial water table
Activation values
Spatial function for the initial conditions
No initial condition
6.3 Time stepping - temporal integration
Finite element temporal integration formulation
Problems with time step sizes
General rules for setting time steps
Adaptive time stepping
6.4 Staged / multiple analyses
6.5 Axisymmetric
6.6 Plan view (confined aquifer only)
7 Functions in GeoStudio
7.1 Spline functions
Slopes of spline functions
7.2 Linear functions
7.3 Step functions
7.4 Closed form curve fits for water content functions
7.5 Add-in functions
7.6 Spatial functions
8 Numerical Issues
8.1 Convergence
Option 1: Vector norm of nodal heads
Option 2: Gauss point conductivity difference
Viewing convergence process
8.2 Water balance error in a transient analysis
8.3 Steep material property functions
8.4 Improving convergence
Conductivity function control parameters
Slope of water content function
8.5 Gauss integration order
8.6 Equation solvers (direct or parallel direct)
8.7 Time stepping
Automatic adaptive time stepping
9 Flow nets, seepage forces, and exit gradients
9.1 Flow nets
Equipotential lines
Flow paths
Flow channels
Flow quantities
Uplift pressures
Limitations
9.2 Seepage forces
Forces on a soil element
9.3 Exit gradients
Gradients
Critical gradients
Geometry considerations
Effective stress and soil strength
Flow velocity
9.4 Concluding remarks
10 Visualization of Results
10.1 Transient versus steady state results
10.2 Node and element information
10.3 Graphing node and gauss Data
10.4 “None” values
10.5 Water table
10.6 Isolines
10.7 Projecting Gauss point values to nodes
10.8 Contours
10.9 Animation in GeoStudio 2007
10.10 Velocity vectors and flow paths
Calculating gradients and velocities
Velocity vectors
Flow paths
10.11 Flux sections
Flux section theory
Flux section application
11 Modeling Tips and Tricks
11.1 Introduction
11.2 Problem engineering units
11.3 Flux section location
11.4 Drain flux values
11.5 Unit flux versus total flux?
11.6 Flow above phreatic line
11.7 Pressure boundary with depth
11.8 Summing graphed data
12 Illustrative Examples
12.1 Homogeneous dam with toe drain
12.2 Steady state flow under a cutoff wall
12.4 Seepage through a dam core with varying Ksat values
12.5 SEEP/W generated pore-water pressures in SLOPE/W stability
analysis
12.6 Kisch – Infiltration through liners and caps
12.7 Sand box verification
12.8 Rapid filling and drawdown of reservoir
12.9 2D Pond Infiltration and water table mounding
12.10 Filling pond (H vs V functions)
12.11 Road ditch ponding during rainfall
12.12 Drains
12.13 Radial flow to a well
12.14 Dissipation of excess pore water pressure
12.15 Lysimeter study
13 Theory
13.1 Darcy’s law
13.2 Partial differential water flow equations
13.3 Finite element water flow equations
13.4 Temporal integration
13.5 Numerical integration
13.6 Hydraulic conductivity matrix
13.7 Mass matrix
13.8 Flux boundary vector
13.9 Density-dependent flow
14 Appendix A: Interpolating Functions
14.1 Coordinate systems
14.2 Interpolating functions
Field variable model
Interpolation function derivatives
12.3 Steady state flow under a cutoff wall with anisotropy
14.3 Infinite elements
Mapping functions
Pole definition
References
Index 304
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