The SlopeStab (for Mac computers) and SlopeStabi (for iPhone’s and iPad’s), app’s that evaluate total factor of safety for slopes in soil and weak rocks (evaluate risk for landslides), have been upgraded to handle clays with linearly changing cohesion with depth.. 

The app’s are restricted to analysing according to simplified Bishop and Swedish (ordinary) method of slices. Geometry wise only circular failure arcs are analysed but both app’s share the same input files so you can easily bring your stability thoughts out in the field. The app’s are available at Apple app store’s.