Constitutive and multi-block modeling of landslides on saturated sands along slip surfaces

The paper first proposes and validates a constitutive model simulating the change of resistance along slip surfaces in sands both for the undrained and drained cases, measured in ring shear tests. The proposed model is based on (a) the critical state theory and (b) the assumption that the critical state changes as a result of grain crushing, in terms of shear displacement. Model parameters depend only on sand type. Then, the developed constitutive model is implemented in the recently-proposed multi-block sliding system model for the prediction of the triggering and deformation of earthquake-induced landslides. The improved model is applied successfully at a simple slope and at the well-documented Nikawa slide triggered by the 1995 Hyogoken-nambu earthquake. Parametric analyses illustrated the ability of the improved model to simulate the effect of the applied motion, sand density, saturation conditions and geometric rearrangement on the seismic displacement of slopes.