Towards Physics-Based Large-Deformation Analyses of Earthquake-Induced Dam Failure

Earthquake-induced damage to embankment dams have been frequently reported in the past earthquakes. Embankment dam failure triggered by ground shaking is a complicated nonlinear, progressive, large-deformation process. Yet, conventional computational method has significant limitations in modeling the large-deformation failure process due to mesh distortion and numerical issues. In this study, a two-phase hydro-mechanically coupled Material Point Method (MPM) is developed, which provides a new tool to investigate fully nonlinear mechanism of dam failure and post-failure large-deformation behavior under earthquake shaking. The progressive failure process of the embankment dam, including slip triggering and post-failure large-deformation behavior, are studied by the developed MPM. As an example, the case history of Lower San Fernando dam failure during the 1971 M6.6 San Fernando earthquake in California is simulated. Subjected to strong earthquake loading, the dam materials experience significant loss of strength due to liquefaction. The entire failure process of the dam is captured by the model, indicating great promise of the MPM method in dam failure analyses.