Reliability analysis of excavated slopes in undrained clay

A novel approach based on the upper bound theory is proposed to assess the stability of excavated slopes with spatially variable clay in undrained conditions. The proposed random limit analysis is a combination of the deterministic slope stability limit analysis together with random field theory and Monte Carlo simulation. A series of analyses is conducted to verify the potential application of the proposed method and to investigate the effects of the soil undrained shear strength gradient and the spatial correlation length on slope stability. Three groups of potential sliding surfaces are identified and the occurrence probability of each sort of failure mechanism is quantified for various slope ratios. The proposed method is found to be feasible for evaluating slope reliability. The obtained results are helpful in understanding the slope failure mechanism from a quantitative point of view. The paper could provide guidance for slope targeted local reinforcement.