Probabilistic failure analysis of infinite slopes under random rainfall processes and spatially variable soil. Issue 1 (2nd January 2019)

• Record Type: Journal Article
• Authors: Yuan, Ji; Papaioannou, Iason; Straub, Daniel
• Is Part Of: Georisk. Volume 13:Issue 1(2019)
• Page Start: 20
• Page End: 33
• Publication Date: 2019-01-02
• Subjects: Rainfall-induced landslide -- random rainfall simulation -- unsaturated flow -- infinite slope -- subset simulation; Environmental risk assessment -- Periodicals; Hazardous geographic environments -- Risk assessment -- Periodicals; Reliability (Engineering) -- Periodicals; Risk management -- Periodicals; 624.151
• DOI: 10.1080/17499518.2018.1489059
• Languages: English
• ISSNs: 1749-9518

Abstract

ABSTRACT: Rainfall-induced landslides occur during or immediately after rainfall events in which the pore water pressure builds up, leading to shallow slope failure. Thereby, low permeability layers result in high gradients in pore water pressure. The spatial variability of the soil permeability influences the probability such low permeability layers, and hence the probability of slope failure. In this paper, we investigate the influence of the vertical variability of soil permeability on the slope reliability, accounting for the randomness of rainfall processes. We model the saturated hydraulic conductivity of the soil with a one-dimensional random field. The random rainfall events are characterised by their duration and intensity and are modelled through self-similar random processes. The transient infiltration process is represented by Richards equation, which is evaluated numerically. The reliability analysis of the infinite slope is based on the factor of safety concept for evaluating slope stability. To cope with the large number of random variables arising from the discretization of the random field and the rainfall process, we evaluate the slope reliability through Subset Simulation, which is an adaptive Monte Carlo method known to be especially efficient for reliability analysis of such high-dimensional problems. Numerical investigations show higher probability of slope failure with increased spatial variability of the saturated hydraulic conductivity and with more uniform rainfall patterns.