A study of overtopping breach process with soil-water erosion using improved smoothed particle hydrodynamics

The overtopping breach of embankment is a kind of serious geological disaster which involves complex soil-water coupling and interaction mechanisms. To investigate the coupling mechanical behavior in the overtopping breach processes of embankments, a unified updated Lagrangian form of governing equation system based on improved smoothed particle hydrodynamics (SPH) is proposed. In the present work considering soil-water interaction, the embankment soil is described using an erosive soil model with strength reduction to describe the fine particle migration. A simple inflow boundary is constructed based on the equation of water balance to improve the numerical efficiency. After validation of the proposed model and approach with experiment, two-dimensional as well as three-dimensional cases with different soil cohesion are investigated, in which the evolution of the soil-water profile is tracked. In the case of three-dimensional model, four typical failure modes of the overtopping breach process of embankment are reconstructed. Results show that the increase in soil cohesion can induce a steep downstream slope during overtopping breach, which is related to the representative phenomenon called "headcut" erosion.