Plane failure analysis of rock slopes: A reliability approach

Abstract

ABSTRACT Probabilistic methods enable the rational treatment of uncertainties in the design and safety evaluation of rock structures, and consequently have become popular in mining engineering during recent years. In this study, advanced first-order second-moment (FOSM) method proposed by Hasofer and Lind (1974), that eliminates most of the limitations of the other probabilistic techniques, is taken as the reliability model in the analysis of plane failure. The advanced FOSM reliability approach treats the friction angle, cohesion and discontinuity orientation parameters as random variables considering the mean values, variances and correlation characteristics. The effects of ground water level and slope height on the design slope angle and the risk of slope failure are investigated together with the sensitivity of the reliability index to the level of uncertainty in the basic variables. Additionally, based on the criterion of minimizing expected total cost, the optimal slope angle to be used in design is identified.