Modelling of diffuse failure mechanisms of catastrophic landslides

This paper presents a theoretical and numerical framework to model the initiation mechanisms of catastrophic landslides. Attention is paid to the mechanism of failure referred to as diffuse, characteristic of soils presenting very loose or metastable structures, as in the case of the liquefaction of a sand layer induced by an earthquake, where the effective stress approaches zero as the pore pressure increases. The equations describing the coupling between the solid skeleton and the pore fluids are presented following an Eulerian approach based on mixture theory that can provide a unified formulation for both initiation and propagation phases. The system of partial differential equations is then discretized using the classical Galerkin finite element method and neglecting the convective terms. A simple improvement of the Generalized Plasticity model is introduced to deal with bonded geomaterials and to represent the mechanical collapse of such materials. The use of an implicit integration scheme guarantees the efficiency of the numerical convergence. (C) 2004 Elsevier B.V. All rights reserved.