KEY FEATURES

SIGMA/W MODELS A FULL RANGE OF DEFORMATION PROBLEMS

STAGED FILL OR EXCAVATION DESIGN

The rigorous stress-strain formulation of SIGMA/W, and the seamless workflow of GeoStudio, simplifies the analysis of complex staged construction problems involving cut slopes and fill placement. Simulations of this nature are required to simulate the construction of earth and rock fill embankments, tailings dams, railway and roadway cuts, and more. SIGMA/W’s coupled stress-strain and water transfer formulation makes it possible to also analyze the simultaneous generation and dissipation of excess pore-water pressures, allowing for the design of sub-surface drainage systems with the software.

STABILITY AND DEFORMATION OF SLOPES

SIGMA/W can be used to model the deformation of natural and cut slopes under a variety of loading conditions resulting from changes to the groundwater flow system, strength loss due to strain-softening, and construction activities. SIGMA/W’s Strength Reduction Stability (SRS) technique can be used to calculate a safety factor against failure while simultaneously providing information about deformations resulting in strength loss.

REINFORCEMENT AND SLOPE STABILIZATION

Deep excavations for civil, geotechnical, and mining applications often involve complex soil-structure interaction. The rigorous structural element formulations, combined with a comprehensive material model library, make SIGMA/W the ideal tool for modeling struts, pile and sheet walls, anchorage, tunnel lining, and more. SIGMA/W’s Stress Redistribution analysis also makes it possible to simulate load transfers and structural responses for projects involving slope stabilization by means of engineered structures (e.g. soldier pile wall). In all cases, SIGMA/W can be used to ensure that the structures are designed to safely carry the loads and to ensure that overall stability is established with an acceptable margin of safety.

VIEWING THE ANALYSIS RESULTS

Once you have solved your analysis, SIGMA/W offers many tools for viewing results. View a deformed mesh or displacement vectors at any magnification. Generate contours or x-y plots of more than 30 computed parameters, including deformation, total and effective stress, strain and pore-water pressure. Display shaded yield zones. View the stress state at any node or element Gauss point as a Mohr Circle with the associated space-force diagrams. Plot shear or moment distribution along structural elements. Then prepare the results for your report by adding labels, axes, and pictures, or export the results into other applications such as Microsoft® Excel® for further analysis.

TYPICAL APPLICATIONS

SIGMA/W can model almost any stress or deformation problem, including:

- Settlement of footings, fluid-filled tanks, or earth structures
- Deformation within or underneath an embankment or earth dam
- Closure around a tunnel
- Lateral movement of braced or anchored excavations and surface settlement around the excavation
- Floor rebound of open-pit, sloping excavations
- Volume changes (uncoupled consolidation or heave) resulting from pore-water pressure changes

- Staged fill placement, earth removal
- Soil-structure interaction, including free un-bonded anchors, cross excavation struts, and trusses
- Fully-coupled consolidation analysis
- Simulation of tailings deposition
- Permanent deformations resulting from strength loss
- Strength reduction stability
- plus many more!

THE POWER OF INTEGRATION

SIGMA/W offers simple but powerful analytical capabilities when used in combination with other GeoStudio products.

FORMULATION

SIGMA/W is formulated for 2-dimensional plane strain or axisymmetric problems using a small displacement, small strain, incremental load formulation. For each load step, incremental displacement at each node resulting from the incremental load is computed and added to the displacement at the beginning of the load step to give the total displacement. For soil models with nonlinear material properties, SIGMA/W solves the equations iteratively using the Newton-Raphson technique; soil properties are updated every iteration until a converged solution is achieved.

You can simulate the filling and excavation of materials by activating or deactivating regions at various stages of the construction process. SIGMA/W can be used with SEEP/W for uncoupled consolidation analyses. SEEP/W calculates transient pore-water pressure changes due to the applied load, while SIGMA/W calculates deformations resulting from the pore-water pressure changes.

FEATURES

- Analysis types include drained total and effective stress, undrained total and effective stress, 2D plane strain, 3D axisymmetric, consolidation and swelling, and insitu stress.
- Constitutive soil models include linear-elastic, anisotropic linear-elastic, elastic-plastic, and Modified Cam-clay.
- Boundary condition types include X and Y displacements, forces, pressures, and spring constants, as well as self-weight gravity loading.
- Structural beam and bar elements for soil-structure interaction.
- Staged loading for fill placement or earth removal.
- Uncoupled volume change due to pore-pressure changes.
- Fully-coupled stress-pore pressure analyses.
- User-defined Add-In constitutive models.

INTEGRATION WITH OTHER APPLICATIONS

USE SIGMA/W STRESSES IN SLOPE/W OR QUAKE/W

Using finite element computed stresses in SLOPE/W makes it possible to conduct a rigorous stability analysis using the same stress values resulting from the deformation analysis. In addition, you can use SIGMA/W stresses as the initial stress state for a dynamic earthquake analysis in QUAKE/W.

USE SIGMA/W PORE-WATER PRESSURES IN SLOPE/W OR SEEP/W

Excess pore-water pressures generated by static loading, such as fill placement, can be brought into SEEP/W to study how long it takes to dissipate the excess pressures in the foundation. You can use SLOPE/W to analyze the effect of these excess pressures on stability during construction, allowing you to determine the need for staged loading.

ENGINEERING METHODOLOGY BOOK

The included SIGMA/W engineering methodology book discusses the whys and hows of modeling, as well as the theory and formulations behind the SIGMA/W product. Stress-Deformation Modeling with SIGMA/W is a full-length book about proper modeling techniques: how to think before, during and after setting up and solving a model. The book includes chapters devoted to:

- Numerical Modeling: What, Why and How
- Fundamentals and Practical Modeling Considerations
- Geometry and Meshing
- Material Models and Properties
- Bounday Conditions
- Analysis Types
- Coupled Stress-Pore Pressure Analysis
- Functions in GeoStudio
- Structural Elements
- Staged Construction Sequencing
- Numerical Issues
- Visualization of Results
- Illustrative Examples
- Theory

MINIMUM SYSTEM REQUIREMENTS

- Microsoft® Windows® 10, Windows® 8.1, Windows® 8, Windows® 7 SP1
- Intel® Pentium® 4 or better, or AMD Opteron™ or Athlon™ 64 or better.
*(GeoStudio is optimized for multi-core Intel processors)* - 1 GB hard disk space
- 1024×768 screen resolution.

For 3D features, your graphics card must support Direct3D® Feature Level 10_1 or greater.

This includes graphics cards such as (and newer than):- Nvidia® GT 300
- ATI® Radeon® HD 4000 Series
- Intel® HD Graphics 3000/2000

- Microsoft® .NET 4.0 will be installed automatically if it is missing.

SUPPORTED VIRTUAL MACHINES

- The latest release of GeoStudio can be run on these VM platforms:
- VMware® ESXi™ 5.5 and 6.0
- VMware® Workstation™ 11 and 12
- Microsoft® Hyper-V® on Windows Server® 2016, 2012 R2, 2012, and Windows® 10
- Citrix® XenServer® 6.2, 6.5 and 7.0