Failure of Concrete-Face Sand-Gravel Dam Due to Water Flow Overtops

Abstract

Based on field investigations and model tests on Gouhou concrete-face sand-gravel dam (CFSGD) breach case, a simplified numerical model for CFSGD breach was developed. The two major highlights of the model are the adoption of total-load nonequilibrium transport equation to simulate the erosion process of sand gravels with a wide range of gradation, and the establishment of an analogy to simulate the failure process of each concrete-face slab under various loads during the dam breaching process. The analysis of the case study of Gouhou dam breaching was used to verify the proposed model, and the results showed relative errors of less than ±15% for the output of breach parameters. The sensitivity analysis indicated that the soil erodibility and grain-size distribution significantly affect the prediction of breach flow of the dam.