CFD-DEM Modeling of Piping Erosion Considering the Properties of Sands

Internal erosion has been reported to account for about 50% of the dam and levee failures throughout the world. This paper presents a coupled computational fluid dynamics and discrete element method (CFD-DEM) approach to model piping erosion process in sandy soils. The soil-flow interactions are explained by exchanging the momentum exchange between the two phases. Specifically, flow forces such as buoyant force, drag force and viscous force are considered. The various stages of piping erosion including initial movement, progressive heave and total heave are captured. The required hydraulic gradients to activate the stages are found to be greater than the critical gradient determined by Terzarghi's theory. In addition, the required hydraulic gradients also change with soil properties including specific gravity and particle size distribution.