Stability analysis of a rock slope: Fully-probabilistic approach

Abstract

Stability analysis of rock slopes is an exercise that poses a variety of challenges to a rock engineer. Field information is often lacking and subjective modelling of the rock mass is required. Expert judgment also influences the quantification of the targeted safety level, reflecting the confidence of the designer in his own assumptions and hypothesis. With the introduction of the EN1997 in Europe, structural reliability concepts were brought to the design of geotechnical structures, now also including rock masses after its current revision. Yet, fully-probabilistic methods are still considered valid alternatives to the partial safety method recommended there. Understanding how to address rock engineering problems from a probabilistic perspective becomes essential to move beyond the traditional practice. In this study, a simple problem relating to the stability of a rock slope is explored. Limit states for foreseeable failure mechanisms are defined and the system reliability problem is formulated and solved.