Numerical modelling of river embankment failure due to overtopping flow considering infiltration effects

Abstract

This paper reports laboratory experiments and numerical simulations of river embankment failure due to overtopping flow for different sediment sizes and different saturation conditions of embankment body. The effects of saturation and sediment size of embankment materials on the erosion process are discussed based on the results of the laboratory experiments. A numerical model is proposed to simulate the erosion process of embankments by overtopping flows. The proposed model considered the effects of infiltration process and resisting shear stress due to suction of unsaturated sediment. To simulate the embankment erosion phenomenon, the numerical model consists of four modules: two-dimensional (2D) shallow-water flow, seepage flow, sediment transport using a non-equilibrium model framework, and 2D slope stability. The validity of the developed model is tested using experimental data on embankment erosion. The numerical results on progressive embankment erosion agree well with the results of the sandy river embankment experiments.

Keywords:

• Erosion due to overtopping flow
• river embankment
• seepage flow
• suction
• unsaturated soil

Acknowledgements

This work was supported by Grant-in-Aid for Scientific Research (B) (No. 22360197) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan; and the JSPS AA Science Platform Program (Coordinator: Dr. Hajime Nakagawa). It also received support from the Kyoto University Global COE Program (GCOE-ARS).