Non-homogeneous embankment dams overtopping flow: experimental hydraulic breach results by different scenarios

The overtopping phenomenon is the most common reason of embankment dams’ failure. In current research, the physical modeling of non-homogeneos embankment dams has been performed; and its hydraulic outcomes were then compared with a benchmark model through providing a four-scenario framework. Also, the results analyzed in three stages of dam breach: initiation, development, and the end. The development stage includes the most changes in breach geometry; peak discharge occurrence; and the most sedimentation in the downstream channel bottom. In first scenario, in which the rectangular groove was not excavated in the crest middle; the greatest reduction in breach time was occurred by 60%; and the peak discharge grew by 22%. In second scenario, when shell gradation d50 varied from 0.5 to 1.7 mm; the peak flow discharge increased by 24%; and breach time decreased to 33%. When the impenetrable core clay weight increases by 10%; less difference was observed between breach hydrographs in the third scenario. In addition, with 20% growth in core clay weight; the highest enhancement of peak discharge was recorded in the fourth scenario by 28%. Furthermore, the fourth scenario proved an important influence of the core cohesion on the breach hydrograph. By drawing the sedimentation patterns; the volume and mass of eroded material were calculated. The simultaneous measurements of breach geometry, flow hydrograph, and sedimentation patterns are the unique achievements of the present research, indeed.