Reliability analysis of rainfall induced slope instability of unsaturated soil slopes
The paper pertains to the application of a simple procedure for reliability analysis to natural slopes of unsaturated soils after rainfall infiltration considering the uncertain system parameters as random variables. Analysis has been done within the framework of the well known 'infinite slope' limit equilibrium model suitably modified to take into account the shear strength of an unsaturated soil. Analysis of the time dependent process of infiltration and the progression of the wetting front is based on a modified form of the widely known 'Green-Ampt model'. Reliability analysis has been carried out based on the simple Taylor series (MVFOSM) method. The results obtained for an illustrative example predict a much earlier occurrence and a much shallower location of the potential slide than that predicted by the conventional deterministic analysis. A reliability-based sensitivity analysis reveals that the angle of internal friction has the most dominating influence on the probability of failure of the slope. 2014 Taylor & Francis Group.