171 / 2024-02-26 14:58:12

The characteristics and harm of valley width deformation after impoundment of reservoir in large-scale hydropower projects

Valley width deformation；Rock mass creep；elastic-creep model; Baihetan reservoir; Xiluodu reservoir

In recent years, the problem of valley width deformation in domestic hydropower projects has attracted more and more attention, and the continuous development of deformation is a serious threat to dam safety. This paper statistics the cases of valley width deformation in hydropower projects at home and abroad, summarizes the research results and harm of valley width deformation, and points out the successful experience and shortcomings of the previous research work. Taking the two large hydropower projects of Xiluodu and Baihetan Reservoir as the key analysis objects, the engineering geological and hydrogeological conditions of the two reservoirs are analyzed. The characteristics and harm of valley width deformation are summarized. The evolution of the seepage field after the impoundment of two reservoirs is discussed, and the mechanism of valley width deformation is put forward through comparative analysis. It is pointed out that basalt creep deformation is the main reason for valley contraction of the two hydropower stations. After the impoundment of the reservoir, the effective stress decreases with the increase of pore water pressure in the aquifer, and the creep deformation after rock mass deterioration is the main deformation mechanism. Finally, the necessary conditions of valley width deformation are pointed out, the development trend and harm of the deformation are predicted, and the prevention and control measures of the deformation are discussed. This work will provide technical support for the safe operation of hydropower projects.