Study on influence of construction and water storage process on valley deformation of high arch dam

The phenomenon of abnormal valley shrinkage deformation in the process of high arch dam construction and water storage has become a hot issue at present. This paper relies on Jinping I high arch dam in China; the influence of dam pouring and reservoir impoundment process on valley deformation is studied. Based on the unsaturated relative permeability coefficient model of rock mass, the unsaturated relative permeability coefficient model of structural plane and its filling is established. Through the coupling analysis of stress and seepage and the comparison of multiple working conditions, the numerical simulation results are in good agreement with the measured data. The results show that the valley deformation is shrinkage whether or not the construction and water storage process is considered. The development regularity of valley deformation is mainly influenced by the impoundment process, and the magnitude of valley shrinkage is mainly controlled by the dam pouring process. In the process of unsaturated seepage, the magnitude of valley deformation is positively correlated with the saturation of rock mass and the saturation and void ratio of structural plane fillings. The deformation of upstream valley amplitude is obviously greater than that of downstream. It can be seen that the influence of dam construction and water storage process on valley shrinkage cannot be ignored. It should be one of the important factors to be considered in the analysis of dam abutment slope deformation and valley deformation.