Comprehensive Evaluation of Sensitivity of Surrounding Rock Parameters for Underground Powerhouse Experience Support

At present, the design and construction of underground powerhouse support are still in the experimental stage. Moreover, before the construction of the underground cavern group, the mechanical parameters of the surrounding rock mass cannot be accurately obtained. During the implementation process, these reasons may cause adjustments to the construction and design plans. To comprehensively evaluate the sensitivity of surrounding rock parameters, we used the multi-indicators, which have certain guiding significance for the accurate acquisition of surrounding rock parameters and the adjustment of empirical support schemes. This study combines the initial geological conditions of the underground powerhouse caverns of the hydropower station and the support scheme. We selected the key position deformation of the lining and the cable stress as the evaluation indicators. The elastic modulus, Poisson's ratio, friction angle, and cohesion are the influencing factors for the comprehensive evaluation of sensitivity. The results show that the elastic modulus is a highly sensitive parameter for the empirical support scheme, the friction angle is a middling sensitive parameter, and the Poisson's ratio is a low-sensitivity parameter. Moreover, it is reported that sensitivity is related to the selection of indicators.