Simplified framework for system reliability analysis of slopes in spatially variable soils

This paper proposes a simplified framework based on multiple response surface method (MRSM) and Monte Carlo simulation for efficient system reliability analysis of slopes in spatially variable soils. Equivalent spatially constant parameters, which are calculated from an explicit random variable model, are used within this framework to characterise the soil spatial variability such that conventional MRSM can be efficiently performed. In addition, a variance reduction strategy is proposed to enable the framework to be applicable to slope reliability problems that involve more than one type of shear strength. Two slope examples are studied to illustrate the accuracy and efficiency of the proposed framework, based on which the robustness of the proposed framework against various statistics, such as the anisotropic spatial variability, is fully demonstrated by numerous parametric studies. Results show that the proposed framework accurately evaluates the slope reliability considering spatially variable soils in a relatively efficient manner. The proposed framework provides a promising tool for an efficient slope reliability analysis.