Reliability Analysis of Unsaturated Slope with Spatially Correlated Soil Properties

Abstract

A non-intrusive stochastic finite element method is proposed for reliability analysis of unsaturated slopes considering the spatial variability of hydraulic parameters and shear strength parameters. The Karhunen-Loeve (KL) expansion technique is employed to discretize cross-correlated lognormal random fields. The factor of slope safety is explicitly expressed as input random parameters using the Hermite polynomial chaos expansion. The Latin hypercube sampling technique is used to calculate the unknown coefficients of polynomial chaos expansion. An example of reliability analysis of an unsaturated slope under the steady-state seepage flow is presented to demonstrate the validity of the proposed method. The results indicate that the proposed method can effectively evaluate the reliability of unsaturated slopes considering spatially varying soil properties. The polynomial chaos expansion combined with the Latin hypercube sampling technique can effectively estimate the probability of slope failure at a relatively low level.