A dynamic SNS-PFEM with generalized-α method for hydro-mechanical coupled geotechnical problems

The node-based smoothed particle finite element method (NS-PFEM) is computationally efficient with pure linear interpolation, while some intrinsic defects hinder its application in dynamic and hydro-mechanical coupled analysis. This study proposes a dynamic implicit stable NS-PFEM (SNS-PFEM) with some features: (1) the subdomain-based stress point stabilization is applied to overcome the spurious non-zero energy mode of NS-PFEM; (2) the polynomial pressure projection is implemented into the dynamic SNS-PFEM to guarantee the pore pressure stabilization; (3) the implicit time marching scheme of generalized-α method to integrate the stabilized equations is derived, which is error-controllable, unconditionally stable regardless of time step and permeability; and (4) an updated Lagrangian remeshing scheme is implemented to deal with the large deformation. The proposed implicit SNS-PFEM is first validated by several benchmark examples, and then applied to analyse the seabed under wave loading, the cutting slope experiment, and the slope failure under seismic loading. All results demonstrate the proposed method is stable and accurate in modelling the hydro-mechanical coupled dynamic problems under small and large deformation with nonlinear soil constitutive models and different drainage conditions.