Run-Out Simulation of a Landslide Triggered by an Increase in the Groundwater Level Using the Material Point Method

Antonello Troncone,Luigi Pugliese,Enrico Conte

doi:10.3390/w12102817

Abstract

Deformation mechanisms of the slopes are commonly schematized in four different stages: pre-failure, failure, post-failure and eventual reactivation. Traditional numerical methods, such as the finite element method and the finite difference method, are commonly employed to analyse the slope response in the pre-failure and failure stages under the assumption of small deformations. On the other hand, these methods are generally unsuitable for simulating the post-failure behaviour due to the occurrence of large deformations that often characterize this stage. The material point method (MPM) is one of the available numerical techniques capable of overcoming this limitation. In this paper, MPM is employed to analyse the post-failure stage of a landslide that occurred at Cook Lake (WY, USA) in 1997, after a long rainy period. Accuracy of the method is assessed by comparing the final geometry of the displaced material detected just after the event, to that provided by the numerical simulation. A satisfactory agreement is obtained between prediction and observation when an increase in the groundwater level due to rainfall is accounted for in the analysis.

Highlights

Landslides often occur after long rainy periods due to changes in pore water pressure on a potential sliding surface [1,2,3,4]
This paper focuses attention on a landslide that occurred at Cook Lake (WY, USA), which was triggered by an increase in the groundwater level owing to rainfall
Several studies were published on this landslide, where useful data can be found such as the location of the groundwater level at the time of the slope collapse

Summary

Introduction

Landslides often occur after long rainy periods due to changes in pore water pressure on a potential sliding surface [1,2,3,4]. Slope stability is generally analysed by considering the deformation processes occurring in the pre-failure and failure phases, by using simplified methods [6,7,8,9,10,11,12] or numerical techniques based on the Lagrangian approach, under the assumption of small strains [13,14,15,16,17] In this latter approach, the computational mesh is embedded in the material and deforms with it, giving rise to numerical shortcomings when elements become highly distorted, as it occurs during the movement of the unstable soil mass. These methods are quite expensive from a computational point of view

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Discussion

Conclusion