GRAIN-SCALE MODELLING OF SATURATED SOILS USING THE GENERALIZED INTERPOLATION MATERIAL POINT METHOD

摘要

Soil dynamics is fundamental to vehicle-terrain interaction. Grain-scale modelling and simulation of soils have gained much popularity in recent years as they make less assumption than traditional continuum constitutive laws. Most of the grain-scale models are developed for dry soils; those developed for saturated soils are of recent origin. The distinct (discrete) element method (DEM) is the most popular in grain-scale modelling of soils. For saturated soils, existing approach couples fluid dynamics with DEM resulting in complicated formulations. In this paper, we propose a direct and simpler approach to model saturated soils using the 'mesh-free' Generalized Interpolation Material Point (GIMP) method where solid (soil grains) and fluid (water) are modelled and discretized into material points in the same manner but with different constitutive equations. A parallel GIMP code, Uintah, was used to study unconfined planestrain compression, as well as indentation tests for cohesionless saturated soils to assess the feasibility of the proposed approach. Load-displacement curves, probability density functions of water pore pressure, equivalent stress and equivalent strain were presented for saturated soils in conjunction with dry soils for comparison.