model = SlopeModel[
<|"Height" -> 10., "SlopeAngle" -> 26.57 Degree,
"FoundationDepth" -> 10., "CrestLength" -> 22.,
"ToeLength" -> 22., "XStart" -> -12.|>,
<|"Regions" -> {<|"Name" -> "Clay", "Base" -> 0.,
"UnitWeight" -> 20., "Cohesion" -> 10.,
"FrictionAngle" -> 20. Degree|>}|>];
sub = SubCriticalSurfaces[model, "Threshold" -> 1.5, "Grid" -> 12];
CriticalitySummary[model, sub]