Many studies of earthen embankment failure from overtopping flow have been conducted in various aspects. Most of them focused on the mechanism of breach, depth and width of erosion, and breach hydrograph. The results were obtained either from both physical and numerical modeling and/or coupling techniques. However, a physical hydraulic model of the effect of breach mechanism under three types; overtopping, beneath structure and piping hole have not been studied. Fixed embankment slopes with scale of 1:8.5 were employed to perform the experiment. It was found that the piping hole case at the toe of embankment was the most severe damage. The iRIC Nays2D numerical model shows a good performance of simulated results in both water flow and breach morphological characteristics, indicating that the model simulation is reasonable.
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