Study On The Dynamic Model Of Foundation And Influence From Seismic Response To Nuclear Power Plant Structure

The interaction of unbounded domain with structure is an important part of the dynamic response analysis.Accurate simulation of radiation damping in unbounded domain is an important basis for structure foundation interaction analysis.Research results show that the influence of unbounded foundation on superstructure is not allowed to be neglected.In order to simplify calculation,many researchers simplify the dynamic model of foundation.Therefore,with the great development of the nuclear power industry,it is of universal and practical significance to study the dynamic model of foundation and influence from the seismic response to nuclear power plant structure.In this paper,the structure of CPR1000 nuclear reactor building is used as the superstructure.The dynamic impedance of foundation under three different influencing factors is studied.Substructure method and direct method are used to analyze the seismic response of RX.In the process of time history analysis,involving the selection of design seismic waves,an improved algorithm for artificial wave fitting of multi damping response spectra is also presented.The specific research contents are as follows:(1)Based on the APDL command flow of the viscoelastic dynamic artificial boundary harmonic response analysis and the MATLAB program of the SBFEM high order transmission boundary are used to solve the dynamic impedance of the fundamental frequency domain of the homogeneous free space,verify the rationality and applicability of the simplified model adopted in this paper.(2)Study on the influence of the dynamic impedance of the half-space foundation,In view of the 3 factors including the depth of foundation embedment,the height of rigid sidewall and the position of soft layer in layered free site,the influence of dynamic impedance of foundation is studied by combining different site simplified models.Comparison of dynamic impedance of foundation with lumped parameter model of semi-infinite homogeneous foundation,(3)In reality,most artificial waves are formed by single damping.Under the influence of multi damping of structural materials,multiple seismic waves are required for the time history analysis,which brings complexity to computation,solution and analysis.In view of the above problem,in order to improve the accuracy and efficiency of the fitting,an improved algorithm is proposed to consider the interrelation between the multi damping response spectra.(4)Study on the seismic response of CPR1000 nuclear power plant structure.Substructure method and direct method are used for dynamic calculation.The amplitude and corresponding frequency of floor response spectrum under different influencing factors are analyzed.