Reliability analysis of Unsaturated Slope Stability Considering Spatial Variability in Hydraulic Parameters

Reliability analysis of slope stability provides a rational framework for slope safety evaluation, which plays a key role in geotechnical decision making for landslide disaster prevention. However, previous studies mainly focused on the slope reliability analysis accounting for uncertainties in shear strength parameters. How to perform reliability analysis of unsaturated slope stability considering the spatial variability of hydraulic parameters remains an open question. This paper aims to systematically investigate the effects of spatial variability of hydraulic parameters on the unsaturated slope reliability. The random fields of hydraulic parameters are derived from the random void ratio field, instead of direct generation, for considering the spatial variability of hydraulic parameters in a rational manner. It is found that the coefficient of variation (COV) and scale of fluctuation (SOF) of void ratio affects the unsaturated slope failure probability significantly. Additionally, the failure probability is sensitive to the selection of auto-correlation function (ACF) in the unsaturated slope reliability analysis.