Hydrologically Driven Slope Failure Initiation in Variably Saturated Porous Media

Abstract

We develop a physics-based slope failure initiation model that considers deformation and strain localization based upon three-phase continuum mixture theory for variably saturated porous media. The spatial and temporal variations in pore pressures needed to drive the slope stability model are simulated with a recently developed integrated hydrology model (InHM). To capture unsaturated soil response, the slope model has been formulated in the context of a three-phase material that explicitly accounts for the effect of the suction stress. The coupling of InHM to a rigorous slope stability model makes it possible, for the first time, to quantitatively investigate at the field-scale the nonintuitive interplay between fluid and hillslope processes that control hydrologically driven slope failure initiation.