Numerical modelling of the initiation of landslides due to increase of water pressure with a multiphase material model

Aim of this poster is the numerical analysis of the initiation of landslides due to increase of water pressure induced by rainfall. The slope is analysed as a multiphase elasto-plastic porous continuum where heat, water and gas flow are taken into account. In particular, the gas phase is modelled as an ideal gas composed of dry air and water vapour, which are considered as two miscible species. Phase changes of water (evaporation-condensation, adsorption-desorption) and heat transfer through conduction and convection, as well as latent heat transfer are considered in the model. The modified effective stress state of the solid skeleton is limited by the Drucker-Prager yield surface for simplicity, with linear isotropic hardening and non associated plastic flow. The macroscopic balance equations are discretised in space and time within the finite element method. The finite element code Comes-Geo has been further developed for this work. The independent variables are the solid displacements, the capillary and the gas pressure and the temperature. Small strains and quasi-static loading conditions are assumed.