You can compute pore water pressures using steady state seepage analysis with Slope. This provides a significant improvement to the way that water pressures are modelled in Slope.

Slope can derive pore pressures for input to stability analysis by carrying out a steady state seepage analysis.  Generating pore pressures in this way requires material permeabilities and boundary conditions (fixed head, fixed flow or phreatic) to be set: Permeabilities are added via material properties, while boundary conditions are defined graphically. The 2D slope section will be automatically meshed, with element sizes adjustable at every node.  Pore pressure results in the finite element mesh are used to derive the pore pressures at the base and down the sides of each slice in the stability analysis.  This avoids the need to use a different program when a more accurate pore pressure distribution is required.

Interpolation of the pore pressures at all slices from the calculated finite element locations can be time-consuming if many slips are analysed at once, and/or if lots of elements are used to calculate the pore water pressures. It is recommended to run analyses with simple groundwater conditions first, and the more detailed analysis once the slip circles of interest have been identified.

The Morgenstern-Price method has become one of the standards in slope stability analysis and is preferred by some checking authorities around the world.  The implementation of this method in Slope allows either a constant relationship between the horizontal and vertical interslice forces or a “half-sine” relationship to be defined.  The method ensures that both moment and force equilibrium are maintained, which is not the case for some of the simpler methods.

Soil strata are defined as polygons rather than left-to-right polylines. This makes drawing models faster and easier, principally by removing the need to generate lists of co-ordinates. Using polygons allows the definition of shapes instead of layers: It is no longer necessary to define the model using layers that cross the entire model. In line with our other geotechnical products, we have also updated the controls of Oasys Slope, adding a new control ribbon. Although the graphical interface has been significantly updated, Slope fully supports importing of old Slope files and will convert the data as required.  This enables easy checking and updating of previous designs.

Slope has COM interface functionality, allowing programmatic interaction with Slope from VBA and Python, for example. This means that Slope can be built into workflows or automation methods. The ability to save models in JSON format provides another way of doing this. JSON is a widely used data format; by adding this ability, we increase Slope’s potential to be used in this way.

Slope provides the following methods of analysis:

• Swedish circle (Fellenius) method
• Bishop’s methods
• Janbu’s methods

The use of these methods allows analysis of both circular and non-circular slip surfaces to be carried out.

A variety of means of specifying water pressure are available including hydrostatic below a phreatic surface, piezometric or Ru values.

A variety of methods of specifying material shear strength are available including drained or undrained parameters which may vary with depth.

Analysis of reinforcing elements – soil nails, rock bolts, ground anchors and geotextiles – to BS8006/BS8081.

Slope has an Input Wizard to enable the user to set up an analysis with ease. It also allows for input via DXF for complex geometries.

A number of Graphical and Tabular outputs are available to users. Graphical outputs are ideal for reports and presentations and tabular outputs can be exported to Excel for further analysis.

Slope enables the user to apply partial factors to their analysis. EC7 partial factors are included but user defined partial factors can be set and applied.