Development of an SPH-based method to simulate the progressive failure of cohesive soil slope

Abstract

The landslide of cohesive soil slope is generally characterized by deformation and failure behaviors involving strain softening and strain-dependent dilation. However, numerical simulation of these complex behaviors remains a challenge since no available soil constitutive model can incorporate all these features. To resolve this problem, a smoothed particle hydrodynamics (SPH)-based approach is developed to simulate the landslide of cohesive soil slope. The cohesive soil slope is modeled as elasto-plastic material with Drucker–Prager yield criterion, and the corresponding softening effect is introduced into Drucker–Prager criterion by treating cohesion as a scalar function of accumulative plastic strain rate. To reduce excessive volume expansion, strain-dependent dilation is fulfilled in a straightforward manner by assuming the dilation angle as a function of volumetric and axial plastic strain increment. Numerical collapse test of cohesive soil pile on a flat plane is conducted to validate the proposed SPH-based approach. The further deformation triggered by softening effect is obtained. The obtained results are compared with those of existing SPH-based method and FEM simulation. Finally, the proposed SPH-based approach is applied to simulate the landslide of an actual cohesive soil slope. The simulation results, including deposit, run out distance, slip surface and final outline, are compared with the field data and classical FEM simulation.