Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Civil Engineering

Embankment dams are the most common type of dams built across the world and they are especially susceptible to failure by overtopping, which is the most common mode of failure of dams worldwide. Understanding the failure mechanisms in embankment dams and levees can lead to better design of flood mitigation, flood mapping, and flood warning systems. Many embankment breach experiments were reported in the literature but they are usually conducted on small scale non-cohesive embankments. A database of 123 events of embankment failure due to overtopping was collected and analyzed using nonlinear regression analysis to provide new equations for calculating several parameters describing the breach process. Moreover, this study uses a large scale physical model constructed on the premises of the Hydraulic Research Institute to model the failure of large scale cohesive and non-cohesive soil embankments. Instantaneous photos, grid of wires, and graded steel rods were used to capture the morphological changes in the embankment during the experiments. A 3D representation of the embankment failure was produced and the stages of the breach process were analyzed. The study showed the great extent to which soil properties affects the failure of embankments due the variation in breach process for embankments with same dimensions but different soil compositions. Finally, the derived breach parameter equations were assessed using the results from the physical model and yielded good agreement for the non-cohesive embankments

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