The 3rd Badong International Geohazards Symposium (BIGS2021)

10 / 2021-10-18 14:56:30

Collapse Prediction Method and Application of Soil Bank Slope in the Three Gorges Reservoir Area under Wave Action

Three Gorges Reservoir area,Bank collapse prediction,Wave action,Soil erosion,Model test

With the long-term operation of the Three Gorges Reservoir (TGR), owing to the fluctuation of the reservoir water level and wave action, the erosion of the soil bank slope continues to advance, the maximum erosion depth has reached more than ten meters, and the bank collapse will continue to expand. Additionally, wave erosion has led to the reconstruction of the reservoir bank, changing the original stability of the landslide and inducing landslide occurrence. Therefore, increasingly serious erosion and bank collapse disasters have become a major concern affecting the safety and sustainable operation of the TGR. The prediction of bank collapse (PBC) on soil slopes is a crucial task for the prevention and control of geological disasters in the TGR. However, the existing methods for PBC in reservoirs rarely consider wave action. PBC parameters mainly rely on surveys and statistics, with no clear standard for determination. Therefore, this paper takes the soil bank slope of the TGR area as the research object, using the soil bank slope’s wave erosion as the dynamic condition to study the PBC method of the soil bank slope in the TGR area. This research’s key issue is the erosion range prediction of the soil bank slope under wave action. For this reason, based on the change law of the current velocity, current thickness and wave run-up, and the mechanical mechanism of the bank slope soil under the wave action, the energy conservation theory was adopted to construct the prediction equation for the range of the wave erosion bank slope. A study on the critical incipient motion conditions of the bank slope soil under water current erosion conditions and a wave run-up test study were carried out to obtain the relevant parameters of the prediction equation. The correctness of the wave erosion bank slope range prediction equation was verified through a wave erosion bank slope model test. Finally, the PBC method proposed in this study was applied.