Overview of User-Defined Surfaces

When the Surface Type in the Surface Options dialog is User-Defined, you can define a specific non-circular slip surfaces. These surfaces can be added to a model with the Add Surface option in the Surfaces menu. Any number of specific non-circular slip surfaces can be added to a model. In order to add a circular slip surface, a circular surface can be imported into the model through importing it as a polyline using the DXF Importer and then assigning it as a non-circular slip surface. This will effectively result in a circular surface.

A supplementary optimization can be applied to slip surfaces, after the initial analysis, in order to locate slip surfaces with an even lower factor of safety. See the Optimize Surfaces topic for details.