Experimental and DEM-CFD Coupling Investigations on the Characteristics and Mechanism of Seepage Erosion for Cohesionless Soil

Abstract

Seepage erosion is one of the main reasons for the local collapse or instability of embankments. To investigate the characteristics and mechanism of seepage erosion for cohesionless soils, model tests using an independently developed seepage erosion device and numerical simulations based on a discrete element method-computational fluid dynamics (DEM-CFD) coupling model were carried out. The results show that the seepage erosion process of cohesionless soil could be characterized by four stages: stable seepage, upward migration of fine particles, boiling of sand samples, and erosion damage. The skeleton structure of a soil sample under seepage flow was continually changed due to the loss of fine soil particles, which resulted in a significant decrease in the sample strength and could, ultimately, lead to the failure of the sample. The results of this study can provide references and bases for the design, construction, and long-term service of embankments or earth dams under complex seepage conditions, reducing the risk of seepage erosion.