Influence of Progressive Failure on Slope Stability

Analytical evidence is presented on the effect of cracking on the slope stability of idealized embankment-foundation sections. The embankment boundary had a circular shape and the bounded mass was homogeneous, isotropic, and linearly elastic. The technique of conformal mapping was the key to calculation of elastic stresses induced by body forces. Various combinations of parameters were applied to represent peak and residual shear strength conditions along the cracked and uncracked portions of the critical surface. The factor of safety against slope instability varies considerably with the degree of development of the crack. Full crack development yields the minimum value for progression from toe to crest. However, partial development of the discontinuity is the least safe state when the direction of development is from crest to toe. The findings seem significant, not only for slope stability, but for all problems involving a potential for progressive failures.