Inversion And Analysis Of Instantaneous And Rheological Parameters Of The Shuibuya CFRD Based On The Improved Response Surface Method

In the aspect of rock-fill dam construction,our country is in the key stage of transition from 200m to 300m level in these years.The high excessive deformation and the security and stability of the dam is an important problem of high concrete face rock-fill dam which needs to be studied and solved in the process.With the development of computer technology and constantly improvement of related calculation theory,the finite element simulation has gradually become one of the effective methods to solve this problem.Accurately determining the mechanical parameters of prototype rock-fill material is the premise to ensure the reasonable and accurate finite element calculation results.Parameter inversion has been proved to be a feasible method to solve this problem.However,a large amount of finite element analysis is required in traditional inversion method which is time-consuming and with low efficiency.The response surface method(RSM)can effectively overcome the above problems.The existing response surface method is only designed for the instantaneous parameters of rock-fill materials,without including the rheological parameters.Based on the original response surface method,considering transient and rheological parameter,by constructing a more reasonable response surface function,and the key parameters selection are analyzed,finally an inversion scheme of both instantaneous and rheological parameters of high rock-fill dam is proposed.The most typical model of domestic concrete face rock-fill dam——shuibuya CFRD is chosen as an example,on the basis of the field monitoring data analysis,take the biggest settlement of the whole dam body and the settlement of a single point as the research object,the final selection of K?n?Kb?m four parameters of Duncan EB model and five rheological parameters were chosen as inversion object,the instantaneous and rheological parameters inversion method based on RSM is adopted to conduct an inversion analysis of the instantaneous and rheological parameters.The results show that in this paper,the structure form of the response surface can predict the finite element calculation value better,the relative error between the calculating value through the response surface function and finite element calculation values is about 1%.Using the inversion parameters achieved by the inversion method,the calculated settlements based on the inversion agree well with the measured one on both values and trends generally,the inversion result is reasonable and reliable.Compared with other inversion analysis method,the proposed inversion method can not only fully consider rheological effect of the rock-fill materials but also significantly reduce the amount of calculation.On the two calculation methods of whether to consider the rheological effect or not,conduct the deformation and stress analysis of shuibuya CFRD separately using inversion parameter.The law of deformation and stress distribution and deformation of rock-fill dam is general in good agreement,and the rheological effect of settlement accounts for about 15%of the total settlement,rheological effect obvious and should not be neglected.