Modelling earthquake-triggered landslide runout with the Material Point Method

Abstract

Landslides triggered by earthquakes cause devastating consequences to downstream infrastructure. The simulation and prediction of these large-strain events remain challenging. The objectives of this paper are i) to validate the Material Point Method (MPM) framework for the study of coseismic landslides, and ii) to compare the capabilities of MPM with mesh-based methods and simplified Newmark-type methods to simulate post-failure runouts. To achieve these objectives, the MPM framework is presented whereby nodal kinematic boundary condition is employed with a moving mesh. Secondly, the framework is validated with a shaking-table laboratory test of a saturated clay slope. Thirdly, a parametric analysis is conducted using 25 real ground motions on a simple theoretical slope. The MPM results are compared to those obtained with mesh-based methods and three state-of-the-art Newmarktype approaches. It is concluded that mesh-based methods are consistent with MPM predictions for small-strain instabilities associated with low energy ground motions (i.e. Arias intensity lower than 4 m/s). When using ground motions with energy above this threshold, mesh-based methods accumulate significant errors associated with bad geometry. MPM results consistently matched permanent displacements predicted with the Newmark-type methods employed in this analysis.