Study on deformation mechanism of reservoir slope near dam during operation period

ABSTRACT: Studying the deformation mechanisms of reservoir bank slopes during the operational period is crucial for arch dam safety. In this study, the evolution process and spatial distribution of deformation in the three typical reservoir bank slopes - Laxiwa, JinPing-I, and Xiluodu are analyzed based on monitoring data. Results indicate that deformation in all three cases is closely related to water level variations over time. Spatially, Laxiwa and JinPing-I exhibit similar deformation patterns, though Laxiwa experiences larger and more localized deformation, whereas Xiluodu shows a wider deformation range with a more uniform distribution. The deformation mechanism of reservoir bank slopes in the three projects is analyzed. The findings indicate that variations in geological conditions are the fundamental factors influencing differences in deformation modes. The geological structure, fractured rock mass and key sliding surface exist in a critical equilibrium state, serving as the primary internal factors. Meanwhile, the increase in pore water pressure and the weakening of mechanical parameters of slope rock mass due to water storage are identified as common external factors. Based on these findings, three typical deformation modes of slope near the dam are identified: structural type slope, stable type slope, and sub-stable type slope.