Abstract: In the construction of the high rockfill dams, it is crucial to accurately determine the mechanical parameters of prototype rockfill materials. Parameter inversion has been shown to be a potential method to solve this problem. In the traditional inversion methods, however, a large amount of finite element analysis is required so that the inversion method is time-consuming and of low efficiency. The response surface method can effectively overcome the above problems. The existing response surface methods are originally designed for the instantaneous parameters of rockfill materials, without including the rheological parameters. Considering both instantaneous and rheological parameters, a more reasonable response surface function is developed, and an inversion scheme is proposed for determining both the instantaneous and rheological parameters of high rockfill dam, which can greatly improves the efficiency and precision of the parameter inversion. The proposed method is adopted to evaluate the instantaneous and rheological parameters of Shuibuya concrete face rockfill dam. It is shown that the calculated settlements of the inversion parameters agree generally well with the measurements with regard to both magnitude and trend, showing that the proposed method is applicable.

Key words: Shuibuya rockfill dam, parametric inversion, response surface method, instantaneous deformation, rheological deformation