Author(s): Wang Yangui; Kuang Shangfu
Linked Author(s): Shangfu Kuang, Yangui Wang
Keywords: Lateral erosion; Bank failure; Bank stability coefficient; Falling failure; Critical caving erosion width
Abstract: The lateral erosion of the bank, especially the caving erosion at the bottom of the bank, plays an important role in the bank failure. The caving erosion mechanism of the concave bank was discussed in this paper with three aspects of the water and sediment movement theory, the dynamic theory and the vortex theory. Based on the comparison of the bank stability coefficient before with that after the lateral erosion, the analysis results showed that the caving erosion makes increases of motive force and its moment and decreases of resistance and its moment, which leads to decrease of the bank stability coefficient. When the caving erosion width reaches to one larger value, the bank will fail. The caving erosion at the bottom of the bank will result in the falling failures, which include the shear, toppling and stress failures. Stability of the falling failure (shear and toppling) was emphatically studied with the critical caving erosion width (CCEW). The CCEW formulas for the shear failure and the toppling failure were derived in this paper for the simple slope bank. The formulas show that CCEW increases with the bank height and bank intensity coefficient, and decreases with the crack depth on the bank surface and the slope angle of the bank.
Year: 2009