SimuIating landsIides using two-phase two-point material point method

Material point method (MPM) is an effective numerical method for large-deformation analysis under unsaturated conditions. In the previous studies, water retention ability and permeability function were assumed to be Independent of soil deformation. Besides, most studies used a single set of material points, so some processes (e.g., the infiltration of free water into unsaturated soil) cannot be modelled. Thereby, a two-point MPM approach has been extended from saturated to unsaturated soils. The required information of soild and liquid phases is carried by two individual sets of material points, with the assumption of zero pore air pressure. GIMP is applied for space discretisation. In the modelling of hydraulic behaviour, the porosity-dependent water retention curve and permeability function are incorporated. A centrifuge test about rainfall-induced unsaturated soil slope failure is simulated to investigate the influence of the porosity-dependent water retention curve and permeability function. Parametric studies demonstrate soil parameters for water retention behaviour and shear strength play significant roles in the slope failure mechanisms.