Simulation of Liquefaction and Retrogressive Slope Failure in Loose Coarse-Grained Material

Flowslides and retrogressive slope failures are usually triggered from a significant drop of shear strength in loose coarse-grained materials, including static liquefaction and successive large deformations. A 4-step procedure is proposed to model these phenomena using the material point method, together with an advanced constitutive model calibrated via inverse analysis. The numerical simulations are performed for a well-documented flume test, which showed that a flowslide was initiated by toe sliding followed by static liquefaction leading to retrogressive failure. First, an advanced hypoplastic constitutive model is calibrated to simulate the observed mechanical behavior of the representative elementary volume (REV) of soil in triaxial tests. Then, these model parameters are used to simulate the slope instability process observed in the flume test. The simulation of triaxial tests and slope instability are satisfactory and highlight important features about the evolution of pore-water pressure and effective stress in a large deformation slope process.