SPH-DEM modeling overtopping failure of earthfill dams

Overtopping failure of earthfill dams is a complex process that involves strong soil-water coupling and structural failure. Physically based numerical models are essential for characterizing the breach mechanism and the failure process. In this study, a dam-break model that considers the combined effects of seepage and overflow is proposed. This model simultaneously solves the governing equations for solid and fluid phases in two different sets of Lagrangian particles. The coupling between water and soil are, respectively, modelled with SPH and DEM particles by considering their interactions, including drag force, buoyancy and particle adhesion. The capillary force caused by the meniscus between soil particles is incorporated to characterize the saturation degree of the soil. The dam-break model is validated by simulating seepage through an earth dam, a small-scale dam-break test, and dam erosion progress. Finally, the proposed model is employed to simulate the overtopping failure of an earthfill dam. Numerical simulations show that the proposed numerical model is capable for capturing the salient features of dam breach. Moreover, some other soil-water coupling processes, such as reservoir water infiltration, dam slope erosion and collapse, breach development, and dam failure, can be predicted by this model as well.