Seepage Model Experiment of Earth Fill Dam Due to Heavy Rains

In recent years, a lot of small earth fill dams have collapsed by occurring torrential rain. It is considered that rainfall infiltration causes the weakening of the levee, which is accompanied by a complex of failure phenomena such as sliding and seepage, but the main cause of the failure has not yet been identified. In this paper, we conduct the model experiments in a 1G gravity field to verify the failure mechanism of small earth fill dams during rainfall. The model experiments are conducted under the assumption of continuous heavy rainfall on the levee composed of sandy soil. The experiments confirmed the development of intermittent small-scale slip failures associated with the increase of pore water pressure and pressure hydraulic head in the levee and the erosion of the slope due to rainfall. The series of results indicate that the erosive failure of the surface soil due to rapid saturation of the surface soil and the development of intermittent slip failures are the main causes of failure when highly permeable levee soils are subjected to very heavy rainfall in a continuous manner.