SPH-DEM simulations of saturated granular soils liquefaction incorporating particles of irregular shape

A coupled smoothed particle hydrodynamics (SPH) and discrete element method (DEM) scheme is presented herein to investigate liquefaction of saturated granular deposits during strong seismic ground motions. Irregularshaped solid particles in the form of polyhedral blocks are utilized to represent soil grains using DEM. In SPH, the fluid domain is discretized into distinct particles carrying local properties of the fluid. Therefore, the presented approach is a fully particle-based technique ideal for handling free-surface and moving boundary problems. The phase coupling is achieved through local averaging techniques and well-established semi-empirical relations quantifying fluid-particle interaction. Level and mildly sloped deposits were subjected to seismic ground motions introduced into the system through the base wall. The results of the performed simulations suggest that both deposits liquefied during strong base excitation due to the contraction of pore spaces leading to large increases in the excess pore fluid pressure that in turn results in significant loss of interparticle contacts and degradation of soil strength and stiffness. In addition, the sloping deposit experienced large lateral displacements, especially, at the shallow soil layers which completely liquefied during the seismic loading.