Probabilistic evaluation on progressive failure in cut slopes

Abstract A method is developed for evaluating the static stability of a cut slope formed by strain-softening soil such as highly overconsolidated clay considering progressive failure as the critical failure mode. The stress condition along a potential failure surface both prior to and after an excavation is determined by finite-element analysis, where the potential slip surface is modeled as joint elements. An elasto-plastic model of hear strength versus strain is also assumed to study the redistribution of the stress released by a local failure. The effect of inherent spatial variation of shear strengths along the slip surface on the progressive failure is investigated by a Monte Carlo simulation procedure. The proposed procedure yields the failure probability as well as the expected length of local failure along an assumed slip surface.