Multiphase medium model for localisation and postlocalisation simulation in geomaterials

It is recalled that negative water pressures are of importance in localisation phenomena of fully saturated, undrained samples of dilatant geomaterials. A model to simulate cavitation phenomena connected with such pore water tractions is developed and implemented in a simplified form in a dynamics code for partially saturated porous media. A case of localisation is studied from the onset of the instability up to the full developed shear band. The weak mesh dependence of the maximum effective plastic strain, due to the employed physical model, is also shown.