Foliation
Soils can be introduced with foliation. It means that along an angle specified in terms of a certain interval, which in turn is introduced as one of the soil parameters <Starting Slope; End Slope> the soil experiences significantly different (usually worse) parameters (c a φ).
If the slope of a slip surface segment or the slope of the interface between blocks is assumed within the interval <Starting Slope; End Slope>, the analysis proceeds with the modified parameters of c and φ.