EROSION OF UNSATURATED RIVER EMBANKMENT DUE TO OVERTOPPING WATER

Abstract

The study on embankment failure is essential to predict potential flood and flood risk management. Significance of soil type and state is essential for the prediction of erosion of embankment due to overtopping. The behaviour of unsaturated soil is different from saturated soil. However, most of the existing embankment breach models do not consider infiltration of water inside the river embankment. Therefore, it is important to study erosion rate of unsaturated embankment of different sediments in different hydraulic conditions for the prediction of outflow discharge and hazard assessment. This study is focused on erosion of unsaturated river embankment caused by overtopping. Shear strength due to suction plays a vital role in erosion of unsaturated fine sediments. A new erosion equation is developed considering shear strength due to suction on an unsaturated bed. The shear strength of an unsaturated bed is correlated with a soil-water characteristic curve. The proposed model is tested for an embankment of different sediment sizes. The numerical model considering suction in erosion rate is capable to predict erosion rate of non-cohesive fine sediments as observed in the experiments.