Uplift Soil—Pipe Interaction Considering Large Deformation and Post-Peak Softening of Dense Sand

Uplift behavior is an important aspect in the analysis of soil—pipe interaction under circumstances of geohazards, such as landslide, liquefaction, faulting, and soil subsidence. Such behavior includes large displacement of pipe, and large deformation and nonlinearity in soil responses. Conventionally, the uplift soil—pipe interaction problem is analyzed by Finite Element Method (FEM), which becomes an error-prone approach when element mesh being distorted in large deformation scenarios. This study aims to analyze such interaction problem for the case of pipe moving upward in dense sand, in which Smoothed Particle Hydrodynamics (SPH) method is used to deal with large deformation of soil. In the soil region with small deformation, FEM is used to reduce the computational time. The post-peak softening behavior of dense sand is represented by the variations of mobilized friction and dilatancy angles depending on plastic shear strain. The hybrid SPH-FEM model of uplift soil—pipe interaction problem is validated with published experimental data. More numerical simulations are subsequently conducted to investigate the uplift resistance, failure mode, and shear band appeared in soil.