ABSTRACT
The factor of safety of a slope can be computed with FLAC by reducing the soil shear strength in stages until the slope fails. The resulting factor of safety is the ratio of the soil’s actual shear strength to the reduced shear strength at failure. This “shear strength reduction technique” has a number of advantages over slope stability analysis with the method of slices. Most importantly, the critical failure surface is found automatically and failure mechanisms involving deforming wedges of soil can be analyzed. The strength reduction technique is illustrated through a number of examples including a simple embankment, rotational failure of a cantilever sheet pile wall, 3D slope stability of a circular hole, and stability of a gravity retaining wall.
