This article addresses the definition of slip surfaces and slope limits in Slide. The following topics are covered:
- Limiting failure surfaces to one material
- Using Slope Limits
- Running analyses on single slip surface
Yes, this is possible. For example, if there is a thin layer, a polyline search can be used to restrict the surface generation to that layer. For more information, see Tutorial 3 on noncircular failure surfaces.
Carrying out an analysis with a Block Search Polyline defined in weak layer
Another option is to set materials in which you do not want a failure surface to propagate to have infinite strength. See the attached file.
Slope with material of infinite strength to limit slip surface location
Yes, in Slide you can use slope limits to force the surfaces through certain portions of the slope. The slope limits options can be found in the Surfaces>Slope Limits menu. The double set of limits should be used if you know the entry and exit points of the surfaces you're interested in. In the case of a failure surface through the entire slope, specify one set near the toe and the other on the crest of the slope. Note that you can also move the limits by right-clicking on the slope limits (they're the little green triangles on the slope surface).
Failure surfaces generated with slope limits imposed at the crest and toe
To do this, automatic creation of surfaces needs to be turned off. If you are doing a circular analysis, simply perform a Grid search and do not define a grid, but define the single circular surface of interest.
Single circular slip surface (user-defined) to be considered in stability analysis
If you are doing a noncircular analysis, set the search method to Path Search and the number of generated surfaces to zero. Then, add the single surface of interest.
Surface Options dialog box (Path Search method is chosen)
Single slip surface (user-defined)
The following instructions outline how to import the critical failure surface from a static analysis into a pseudo-static analysis, and run only that failure surface with the seismic analysis:
- In the Interpret window, for the static analysis, right-click on the surface. A menu will pop up with a Copy (Slide Modeler Format) option. Choose it.
- Go back to the Modeler using the Modeler option in the Analysis menu or the toolbar.
- In the Modeler, choose the Edit>Paste from Interpret menu option.
- The surface of interest will be imported into the modeler. Delete all other surfaces, grids, etc. Use the right-click functionality to quickly delete the search entities. If you are doing a non-circular search, set the number of surfaces to zero. This is so that only the surface of interest is calculated.
- Add the pseudo-static seismic load using the Seismic Load option in the Loading menu of the Slide Modeler.
- Save the file to a new name and run it.