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SLOPE/W and SLOPE3D Features

Integrated into the GeoStudio Suite

SLOPE/W is integrated into the GeoStudio suite, and therefore has access to the GeoStudio features for creating your model, analyzing it, and viewing results. SLOPE3D offers the same integration, meaning that the project set-up, material definition, pore water pressure options, and results interpretation are similar to SLOPE/W. Three-dimensional geometry creation tools are available in GeoStudio's new 3D editor, which is also integrated into the GeoStudio suite. 

Comprehensive Formulation

SLOPE/W and SLOPE3D compute the factor of safety of earth and rock slopes. They can effectively analyze both simple and complex problems for a variety of slip surface shapes, pore water pressure conditions, soil properties, and analysis methods. Using limit equilibrium, SLOPE/W and SLOPE3D can model heterogeneous soil types, complex stratigraphic and slip surface geometry, and variable pore-water pressure conditions using a large selection of soil models. Analyses can be performed using deterministic or probabilistic input parameters in SLOPE/W. Stresses computed by a 2D finite element stress analysis may be used in addition to the limit equilibrium computations for the most complete slope stability analysis available. With this comprehensive range of features, SLOPE/W and SLOPE3D can be used to analyze almost any slope stability problem you will encounter in your geotechnical, civil, and mining engineering projects.

Typical Applications

SLOPE/W and SLOPE3D can model almost any stability problem, including:

  • Natural soil and rock slopes
  • Construction excavations
  • Earthen dams and levees
  • Open-pit highwalls
  • Reinforced earth structures
  • Slope stabilization design
  • Slopes with surcharge or seismic loading
  • Dam stability during rapid drawdown
  • Partially and totally submerged slopes
  • Unsaturated slopes subjected to infiltration
  • Tailings dam stability

A Choice of Many Analysis Methods

SLOPE/W is formulated in terms of moment and force equilibrium factor of safety equations, and supports a comprehensive list of limit equilibrium methods including Morgenstern-Price, Spencer, Bishop, Janbu, and the Ordinary method. Similarly, SLOPE3D offers the ability to use the Morgenstern-Price, Spencer, Bishop, and Janbu methodsThe Morgenstern-Price method, for example, satisfies both force and moment equilibrium. This general formulation makes it easy to compute the factor of safety for a variety of methods and to readily understand the relationships and differences among all the methods.

SLOPE/W can also perform finite element stress-based stability and dynamic stability analyses. It uses finite element computed stresses from either SIGMA/W or QUAKE/W to calculate a stability factor by computing both total shear resistance and mobilized shear stress along the entire slip surface. SLOPE/W then computes a local stability factor for each slice.

Multiple Slip Surface Search Techniques

SLOPE/W and SLOPE3D offer a variety of techniques to search for the critical slip surface. In SLOPE/W, you can define potential slip surfaces by a grid of centers and radius lines, blocks of slip surface points, entry and exit ranges, or fully specified shapes. This provides the flexibility to handle various modes of failure such as rotational, translational, composite, retrogressive, and structure-controlled failures. In SLOPE3D, the slip surfaces can be defined using the entry and exit ranges, or with Cuckoo natural search algorithm.

Rigorous Solution Algorithm

SLOPE/W and SLOPE3D employ a rigorous solution algorithm to cope with highly non-linear problems with difficult convergence. Graphical display of the Factor of Safety vs Lambda plot allows the user to visually inspect the acceptability of convergence for 2D analyses, while the Factor of Safety vs Lambda-X, Factor of Safety vs Lambda-Z, and Factor of Safety vs Sliding Direction are available for 3D analyses.

Comprehensive Pore Water Pressure Definition

Pore water pressures can be defined using piezometric lines, spatial functions, or using the results from other GeoStudio finite element analyses such as SEEP/W. SEEP3D, or SIGMA/W. SLOPE/W and SLOPE3D also accommodate the B-bar and Ru approaches. The defined pore water pressure values can be displayed as contours on the geometry to help you see the PWP values that will be used in the analysis.

Rapid Drawdown Analysis

Rapid drawdown analysis can be conducted using the pore water pressures defined using piezometric lines, transient finite element GeoStudio analyses, or the multi-stage rapid drawdown technique. The water surcharge load is automatically calculated in SLOPE/W at every instant in time.

Reinforcement using Anchors, Nails, Piles, and Geo-Synthetics

A variety of slope stabilization options such as anchors, nails, piles, and geo-synthetics are available in SLOPE/W. A generalized user-defined reinforcement type can be used to model a wide range of structures, including anchors or nails with plate capacity, end-anchored reinforcement, and pile reinforcement with spatially variable shear resistance. Reinforcement loads are calculated with consideration given to tensile capacity, anchorage at the slope face, and stripping in the passive zone. Additional options include factor of safety dependency, load distribution, and orientation of the load. Pull-out resistance for geo-synthetics can be specified or calculated from interface adhesion and shear angle.

SLOPE/W reinforcements may be automatically defined using the vendor reinforcement library, which includes products from Huesker, Maccaferri, TenCate, and Tensar. This functionality was developed in partnership with each vendor to ensure accurate representation of their products.

Reinforcement Sets

Reinforcement Sets provides a convenient means to define multiple reinforcements in a single 2D stability analysis. The Draw Reinforcement Sets and Define Reinforcement Sets windows can be used to add, modify, or delete multiple reinforcement lines that share the same reinforcement properties. A single reinforcement type defined in Define Reinforcements can be applied to all lines within the reinforcement set using a single dropdown box. The spacing between reinforcement lines within a set can be based on a specified spacing between reinforcements or a specified number of reinforcements along the set range. Reinforcement sets can also snap to the ground surface line, so that all lines will remain on the ground surface if the geometry is modified.

Soil Material Models

SLOPE/W and SLOPE3D support a comprehensive list of soil material models including Mohr-Coulomb, undrained, high strength, impenetrable, bilinear, strength as a function of depth, anisotropic strength, generalized shear-normal function, SHANSEP, spatial Mohr-Coulomb and more.

Rock Material Models

The Hoek-Brown and Compound Strength material models in SLOPE/W and SLOPE3D can be used to simulate typical rock materials. Other typical rock material models, such as Barton and Choubey (1977) and Miller (1988), can be handled by using the generalized shear-normal function with or without an anisotropic modifier function.

Transient Stability Analysis

The stability of a slope can be modeled through time with temporal variability in pore water pressures and/or stresses by integrating SLOPE/W with one of the GeoStudio finite element products. Similarly, a SLOPE3D analysis can be integrated with a SEEP3D analysis to determine the influence of 3D groundwater seepage on stability over time.

Limit State Design

Limit state design or load resistance factor design (LRFD) can be handled in SLOPE/W by specifying partial factors on permanent and variable loads, soil unit weight, seismic coefficients and earth resistance, material properties, and reinforcement inputs. In this manner, any design code from around the world can be considered such as Eurocode or the British Standards.

Probabilistic and Sensitivity Analysis

In SLOPE/W, probabilistic and sensitivity analysis can be conducted on almost any input parameter and using a variety of distributions including normal, log-normal, uniform, triangular, or a generalized function. Spatial correlations are handled via a specified sampling distance. Using a Monte Carlo approach, SLOPE/W computes the probability of failure in addition to the conventional factor of safety.

Pseudo-Static and Newmark Dynamic Stability

Earthquake loading can be modeled in 2D stability analyses using seismic loads with various pore water pressure conditions, including the Duncan et al. (1990) two-stage undrained strength method, the two-stage effective stress strength method, or even the dynamic pore water pressures from a QUAKE/W analysis.

Strength Reduction Stability Analysis

SLOPE/W can be integrated with SIGMA/W to perform a strength reduction stability analysis.

Easy Investigation of Slope Geometry

The effect of slope geometry on the calculated factor of safety can easily be analyzed in SLOPE/W by creating multiple analyses in the Analysis Tree and using the Split Region tool.

Fast, Parallel Solving of Slip Surfaces and Analyses

SLOPE/W and SLOPE3D use parallel processing to analyze each slip surface independently, allowing for faster solutions on multi-core processors. Multiple analyses are also analyzed in parallel. You can monitor the solution progress in the Solver Manager window.

Results for any Slip Surface

You can interactively select any analyzed slip surface to graphically display the forces on any slice or information about the sliding mass. You can also display plots of computed results over the slip surface, such as various strength or convergence parameters along each slice.

Results on Multiple Slip Surfaces

Multiple slip surfaces can be displayed on the drawing to investigate different modes of failure and to visualize the variability in factor of safety with slip surface position. These results can be displayed using a slip surface color map, a safety map, or as contours within the grid of slip surface centers. This slip surface list can also filtered to aid you in interpreting the results.

Quickly Replace SLOPE/W Objects in All Analyses

SLOPE/W provides a one-click tool to map objects from one analysis to any other SLOPE/W analysis within the GeoStudio Project. SLOPE/W objects are deleted in the target analyses and replaced with the chosen objects from the current analysis. The objects that can replaced include the tension crack line, slip surface definition, pore-water pressure, point loads, surcharge loads, reinforcement loads, and seismic loads.

Extend SLOPE/W with Add-Ins

Download and install an Add-In for SLOPE/W to model a saturated-unsaturated SHANSEP model.