Study on numerical simulation method of overtopping dam break of concrete faced sand-gravel dam

Based on the field investigation of dam break cases, a numerical simulation method of concrete faced sand-gravel dam overtopping break is proposed. The method is mainly composed of three parts: (1) Aiming at the erosion and scour of vortex flow on dam body, appropriate model is used to simulate the flow movement; (2) The interaction between water flow and sand particles in dam break process is accurately simulated; (3) Based on moment balance method, the failure process of concrete face slab under dead weight and water load is determined. The results show that the proposed mathematical simulation method can accurately simulate the reverse erosion of the dam and the detailed evolution of the face slab break during the dam break process. The relative error between the measured data and the calculated peak breach flow, the development of the breach of the rockfill body, the duration of the dam break and the length of the face slabs are all less than 15%, which verifies the rationality of the numerical model.