Probabilistic Slope Stability Analysis by Finite Elements

TLDR

The study investigates how local averaging influences the probability of failure of a cohesive slope using both simple and advanced probabilistic analysis tools. The authors compare a simple classical slope stability analysis treating shear strength as a single random variable with an advanced random finite‑element method that couples elastoplasticity and random field theory. The RFEM method outperforms traditional techniques by naturally identifying the critical failure mechanism, and the study demonstrates that neglecting spatial variability can underestimate failure probability, contradicting earlier classical analyses.

Abstract

In this paper we investigate the probability of failure of a cohesive slope using both simple and more advanced probabilistic analysis tools. The influence of local averaging on the probability of failure of a test problem is thoroughly investigated. In the simple approach, classical slope stability analysis techniques are used, and the shear strength is treated as a single random variable. The advanced method, called the random finite-element method (RFEM), uses elastoplasticity combined with random field theory. The RFEM method is shown to offer many advantages over traditional probabilistic slope stability techniques, because it enables slope failure to develop naturally by "seeking out" the most critical mechanism. Of particular importance in this work is the conclusion that simplified probabilistic analysis, in which spatial variability is ignored by assuming perfect correlation, can lead to unconservative estimates of the probability of failure. This contradicts the findings of other investigators who used classical slope stability analysis tools.