Analysis of Breach Characteristics and Equilibrium Scour Pattern for Overtopping Induced River Dyke Breach

Abstract

River dykes is an important and effective measure to prevent floods.However, dynamic lateral widening of the breach process, resulting flow and sediment hydrographs and the scour beneath the dyke are poorly understood in current studies. Therefore, this study conducted laboratory experiments and numerical simulations of river dyke breach due to overtopping flow with different sediment sizes. The influence of sediment size of dyke materials on the breach process were discussed based on the results of the laboratory experiments, and a numerical model was developed to simulate the breach process of dykes by flow overtopping.To simulate the dyke breach phenomenon, the numerical model consisted of two-dimensional shallow-water flow, seepage flow, sediment transport and collapse model. The reproducibility of the developed model was tested using experimental data on dyke breach phenomena. The numerical results are well agreed with the results.