Study on prediction method of reservoir bank collapse in loess area

Reservoir bank collapse is a type of hydrogeological phenomena encountered in hydropower projects, and its prediction remains a challenge. The reservoir bank collapse width in the loess area of China is predicted based on the empirical graphical method established by scholars from the Soviet Union; however, the prediction results are quite different from the actual value. In this study, a field investigation was conducted on the bank slope topography after reservoir bank collapse in a loess area. The results showed that the water bank slope remained vertical after the bank collapse, and the accumulation form of the underwater bank slope followed an exponential curve. When the ratio of the water depth to the bank slope height after bank collapse was less than 0.3, there was an accumulation bank slope above the water. When this ratio was greater than 0.3, the accumulation slope was underwater. Based on the water depth and bank slope height after bank collapse, a formula to predict the topography of the underwater accumulation slope was established. Combined with the characteristics of the post-collapse bank slope, a prediction method for loess bank slope collapse was established. The topography of the bank slope predicted by this method was consistent with the field investigation results. The physical and mechanical properties of the bank slope loess and the characteristics of the bank slope were considered, thus overcoming the shortcomings of the conventional graphical method based on empirical parameters. This study has practical significance for prediction of loess bank collapse.