Reliability analysis of slopes considering spatial variability of soil parameters using non-intrusive stochastic finite element method

Abstract

A non-intrusive stochastic finite element method (NISFEM) is proposed for the reliability analysis of slope stability considering spatial variability of soil parameters. Firstly, the Karhunen-Loeve (K-L) expansion method is used to characterize the spatial variability of shear strength parameters, where the wavelet-Galerkin technique is employed to numerically solve the eigenvalue problem of the Fredholm integral equation. Thereafter, the finite element method is used for slope stability analysis, the factor of safety is explicitly expressed using the Hermite polynomial chaos expansion (PCE), and the flow chart of procedure is also presented. Finally, the proposed NISFEM is studied by application to the reliability analysis of a homogeneous slope. The results indicate that the proposed method can greatly improve the calculation efficiency for slope reliability analysis considering spatial variability of soil parameters, and that it provides on effective way for solving complex slope reliability problems. There exists a critical coefficient of variation for slope reliability analysis, which increases as the factor of safety increases. If the spatial variability of soil properties is ignored, it will lead to overestimating the probability of failure when the coefficient of variation of shear strength parameters is less than the critical value. The probability of failure does not always increase with the coefficient of variation when the factor of safety is less than 1. 0. In addition, the correlation between the random fields of effective cohesion and internal friction angle has a very significant effect on the probability of slope failure.