Numerical simulation of earthquake induced landslide run out
Landslides trigged by earthquake have leaded to tremendous deaths, injuries and property loss. Therefore, it is an urgent need to make out the flow characteristics, which is fundamental for hazard assessment and risk evaluation. However, the traditional mesh method, which is based on a framework of solid mechanics, has difficulty in simulating the run out process of landslides considering its deficiency in modelling large deformations. In this paper, the moving particle simulation (MPS) is introduced to simulate landslide run out. To bypass the pressure fluctuation of the original MPS, this method is modified in three aspects including the kernel function, source term of the Poisson equation and the free surface discrimination. The effectiveness of the pressure stability of the modified MPS is verified and validated by two classical benchmark problems: the dam break problem and the static problem. To preferably describe the dynamic feature of landslide, the Bingham constitutive model with the Mohr Coulomb yield criterion is introduced into the modified MPS and an equivalent Newtonian viscosity is adapted to bridge the gap between Bingham flow model and Newtonian flow model. Finally, the proposed method is applied to analyze the landslide run out of the Tangjiashan landslide which is induced by the Ms 8.0 Wenchuan earthquake. The simulated results are compared with the field data to evaluate the effectiveness and the accuracy of the proposed numerical scheme. All calculated results show good agreement with the field data, which indicates that the proposed method is capable to capture the fluidization characteristic of landslide and to reproduce the whole flow process of earthquake induced landslide. This will ultimately help people assess the hazard to reduce or even avoid this disaster in earthquake prone zones.