Model test study on wave-induced erosion on gravelly soil bank slope

Wave erosion on soil bank slopes has become severe with the long-term operation of the Three Gorges Reservoir; however, the progression of soil bank slope erosion varies in different regions. The influence of the physical parameters of the soil mass on the wave erosion bank slope was investigated using a self-designed and manufactured wave erosion bank slope model test device. Physical model tests were conducted on wave erosion bank slopes comprising six groups with different dry densities and gravel contents to obtain the erosion process of the bank slope under wave action. The results show that the higher the dry density of the soil, the stronger the erosion resistance of the bank slope, and the longer the time required for the bank slope to reach a final steady state; the higher the gravel content, the stronger the erosion resistance of the bank slope. Owing to the protective effect of gravel, the time required for bank slope erosion stability was also shortened. Increasing the dry density or gravel content increased the stable slope angle after bank slope erosion. The wave erosion rate of the bank slope was high at the early stage of the test, and the bank slope erosion of each group was effectively completed within 240 min of the start of the test. The erosion rate of each bank slope under wave action decreased exponentially. Based on this, an empirical equation between the wave frequency and bank slope erosion rate was derived, which can be used to determine the erosion process of a bank slope. This research provides technical support for the prevention and control of erosion on soil bank slopes in the Three Gorges Reservoir area.