Effects of spatial variability of soil properties on slope stability

Slope stability analysis is a geotechnical engineering problem characterized by many sources of uncertainty. Some of the uncertainties are related to the variability of soil properties involved in the analysis. In this paper, a numerical procedure for a probabilistic slope stability analysis based on a Monte Carlo simulation that considers the spatial variability of the soil properties is presented. The approach adopts the first-order reliability method to determine the critical failure surface and to conduct preliminary sensitivity analyses. The performance function was formulated by Spencer's limit equilibrium method to calculate the reliability index defined by Hasofer and Lind. As examples, probabilistic stability assessments were performed to study the effects of uncertainty due to the variability of soil properties on slope stability in layered slopes. The examples provide insight into the application of uncertainty treatment to the slope stability and show the importance of the spatial variability of soil properties with regard to the outcome of a probabilistic assessment.