Stabilized Semi‐Implicit Material Point Method for Hydro‐Mechanical Coupled Large Deformation Soil‐Structure Interaction Analyses

ABSTRACT Hydro‐mechanical coupled analysis of geotechnical problems generally poses stability challenges, particularly for soil‐structure interaction problems involving large deformations. This study presents a stabilized semi‐implicit MPM (Material Point Method) treatment based on the incremental fractional step approach to suppress the arbitrary and unphysical pressure oscillations commonly encountered in explicit MPM formulations. The proposed treatment alleviates the restrictive constraints on time increment durations imposed by geomaterial permeability. A frictional contact algorithm incorporating a penalty function is also shown to effectively reduce the formation of spurious gaps and numerical fluctuations over soil‐structure contact areas. The stability of the semi‐implicit MPM treatment is enhanced by introducing artificial compressibility into the pressure Poisson equation, integrating the APIC (Affine Particle‐in‐Cell) scheme for particle‐grid information transfer, as well as adopting the B‐bar approach to mitigate volumetric locking. Additionally, an axisymmetric formulation is developed to enable more efficient modeling of selected classical geotechnical problems. The effectiveness and robustness of the proposed framework are demonstrated against a series of benchmark test cases, including coupled, axisymmetric, dynamic, large deformation and soil‐structure interaction simulations, considering the Modified Cam‐clay constitutive model.