Abstract: According to observed deformation data in underground powerhouse excavation of Baishan pumped storage station, a parameter inversion method based on the response surface methodology is put forward. Using the response surface methodology, the nonlinear relationship between unknown rock mass mechanical parameter and surrounding rock deformation is proposed. Applying the finite element method, coefficients of response surface function are identified. Defining the objective function of parameter inversion, the problem of parameter inversion is changed into optimization. Quasi-Newton optimization algorithm and genetic algorithm are adopted to solve the objective function and get rock mechanical parameters. Based on rock mechanical parameters which are identified by parameter inversion, excavation deformation of surrounding rock is simulated. The study indicates that deformation of surrounding rock simulated by finite element method give a good agreement with in-situ observed data in underground powerhouse.

Key words: parameter inversion, response surface methodology, numerical simulation, Quasi-Newton methods, underground powerhouse