Probabilistic stability analyses of two-layer undrained slopes

Abstract

It is well known that soil properties exhibit spatial variation in both the horizontal and vertical directions that can be modelled as random fields, so this paper will use the random finite-element method (RFEM) to study the reliability of two-layer undrained slopes. Typical applications might include short-term stability of levees or embankments resting on foundation soils with different statistical properties. Results will demonstrate how the difference between the two random fields affects the “seeking out” effect of the failure mechanism, which permits the deeper failure mechanisms to form naturally because of possible lower undrained strengths in the foundation layer. Results will also show the worst-case spatial correlation length that leads to a maximum probability of failure, and demonstrate the worst-case effect becomes less obvious as the mean strength ratio of the two layers increases.