Probability of Failure Occurrence and Recurrence in Rock Slopes Stability Analysis

The paper illustrates the procedures for computing the probability of failure occurrence that represents the potential that a slope can undergo failure due to both the spatial variability of the structural and geomechanical aspects of the joint sets and the existing boundary conditions. The presented approach to a global probabilistic assessment of the rock slopes stability conditions is based on the analysis of the spatial variability of structural aspects of the rock mass, of the uncertainty in geomechanical properties, and of the occurrence probabilities of certain values of seismic forces and rainfall intensities. Finally, the probability of failure recurrence is computed taking into account occurrences, in time, of the external acting forces, so providing an evaluation of the rock slope landslide hazard, that is the probability that an instability event with a given intensity may occur within a reference time period.