ABSTRACT
This chapter concerns the failure of slopes containing discontinuities striking obliquely to the slope face where sliding of a wedge of rock takes place along the line of intersection of two such planes. It explains the structural geological conditions that result in the formation of a wedge formed by two intersecting planes are defined, and the method of identifying wedges on the stereonet. The chapter presents design charts that can be used to find the factor of safety of wedges for which friction is the only component of the shear strength, and there are no external forces such as water pressures or bolting acting on the wedge. The method of calculating the factor of safety of wedges as discussed, of course, simplistic because it does not incorporate different friction angles and cohesions on the two slide planes, or ground water pressures.
