Micromechanical Aspects of Liquefaction-Induced Lateral Spreading

This paper reports the results of model-based simulations of 1-g shake table tests of level and sloping saturated granular soils subject to seismic excitations. The simulations utilize a transient fully coupled continuum-fluid discrete-particle model of water-saturated soils. The fluid (water) phase is idealized at a mesoscale using an averaged form of Navier-Stokes equations. The solid particles are modeled at the microscale as an assemblage of discrete spheres using the discrete element method (DEM). The interphase momentum transfer is accounted for using an established relationship. The employed model reproduced a number of response patterns observed in the 1-g experiments. In addition, the simulation results provided valuable information on the mechanics of liquefaction initiation and subsequent occurrence of lateral spreading in sloping ground. Specifically, the simulations captured sliding block failure instances at different depth locations. The DEM simulation also quantified the impact of void redistribution during shaking on the developed water pressure and lateral spreading. Near the surface, the particles dilated and produced an increase in volume, while the particles at deeper depth locations experienced a decrease in volume during shaking.