If your model includes a Water Table or Piezo Line, then you can specify a different strength type to be used ABOVE the assigned Water Surface for any given material. To use this option:
Select Define Material Properties.
Select a Material from the list at the left of the dialog.
Select the Specify alternate strength type above water surface checkbox, in the Water Parameters section.
Select a different Material from the Use strength type from drop-list.
When you run the analysis, Slide will use a different material strength type above and below the water table or piezo line, according to your material selections. This option can be useful, for example, for clay materials, if you wish to use an Undrained Strength model below the water table, and a Drained strength model above the water table.