Probabilistic analysis of pile-reinforced slopes in spatially variable soils with rotated anisotropy

Abstract

Stabilizing piles have been widely used to remediate landslides and reinforce potentially unstable slopes. Previous investigations on the stability analyses of pile-reinforced slopes, however, were mainly based on deterministic analysis methods, where the spatial variability of soil properties was rarely incorporated. Meanwhile, the assumption of isotropy and horizontal transverse anisotropy in previous studies may bring bias to the slope reliability assessment, and thus the optimization design of piles. This study hence aims at systematically investigating the influence of soil spatially variable anisotropy on statistical characteristics of the factor of safety, failure mechanisms, and probability of failure (Pf) of pile-reinforced slopes. An integrated probabilistic analysis framework is used to obtain an optimal reinforcement scheme of stabilizing piles considering different rotational angles of soil strata. Subset simulation is used to enhance the computational efficiency for reliability analysis. A hypothetical slope and a practical slope are studied as illustrative examples with various parametric studies. Results show that the rotated anisotropy has a significant influence on the performance of pile-reinforced slopes and can largely affect the Pf depending on the strata inclination. For slopes with different rotational angles of strata, the number of critical slip surfaces and the slip band range are different and thereby result in different optimal pile designs.