Stabilized generalized interpolation material point method for coupled hydro-mechanical problems

The material point method (MPM) has been increasingly used to simulate coupled hydro-mechanical problems involving large deformations. However, when addressing saturated porous media with an almost incompressible liquid phase, the classic explicit MPM with low-order interpolation functions is not stable if no further stabilization approach is used. In this study, a solid-velocity-liquid-velocity-based hydro-mechanical governing formulation is adopted to construct a two-phase single-point explicit generalized interpolation material point (GIMP) method. To stabilize this set of formulation, the XPIC(m) (extended PIC of order m) method is extended to erase null space noise and damp high-frequency waves in both solid and liquid phases; additionally, a cell-based averaging approach is adopted to solve locking issues and smooth stress field variables. Several numerical examples have been presented to demonstrate the capabilities of the stabilized coupled GIMP method in simulating coupled hydro-mechanical problems involving dynamic effects and large deformations.