Extensions of the two-phase double-point material point method to simulate the landslide-induced surge process

Landslide-induced surges, as a complex type of fluid-solid coupling problem, are widespread in mountain regions and cause disastrous consequences. In order to reproduce the entire process of landslide-induced surge, by taking full advantage of material point method (MPM) in simulating large deformation of soil and gravity-driven flow of water, the two-phase double-point material point method (TPDP-MPM) was extended: a new algorithm handling the boundary without setting boundary particles was proposed. The classical submarine block-induced surge test and sand column collapse experiment were numerically simulated by the MPM and verified the effectiveness of the program. After that, the multiphase coupling process of Lituya Bay landslide-induced surge was simulated and verified the reliability of the TPDP-MPM code, which have achieved parallel computing by making use of OpenMP model. By comparing the results of numerical simulation with the model experiment, the two-phase double-point material point method can well simulate the starting, propagation, run-up and reflux stage of landslide-induced surge. Moreover, the extension mechanism of landslide-surge disaster chain in both time and space is revealed from the perspective of energy. This study provides a reliable tool for the analysis and assessment of landslide-induced surge disasters.