Simulation of liquefied sand by the Lattice Boltzmann method

The Lattice Boltzmann method is increasingly used in the computational modeling of a wide variety of complex fluid flow problems. Macroscopic quantities like fluid density, velocity, or stress are expressed as moments of a distribution function. The approach can be adopted to simulate non-Newtonian fluids. Laboratory tests on liquefied sand show a shear-thinning behavior, i.e. decreasing viscosity with increasing shear strain rate. Geophysical flows show similar behavior. In the paper, the rheological behavior of the liquefied soil is characterized by means of a non-linear model with upper and lower limiting values of the fluid viscosity. The main features of the applied numerical procedure are described. Typical situations are simulated such as liquefaction-induced flow in a shaking table test, slope failure, and flow around a rigid wall embedded in liquefied soil. The results enable the qualitative assessment of the resulting displacement patterns.