| Along with the construction of Nuclear Power Plant, the study on the inhomogeneous foundation-nuclear power plant dynamic interaction is becoming very important. Against the reactor building of a 1000MW Nuclear Power Plant structure, the dynamic impendence of nuclear power plant on layered foundation is investigated. Regular deterministic seismic analysis methods based on substructure method and direct method are carried out to study the dynamic speciality of nuclear power plant structure on layered soil. It can provide a beneficial reference to evaluate the anti seismic safety of nuclear reactor buildings. This paper reads as follows:(1) The dynamic impedance of foundation is studied by considering the development actualities of dynamic impedance. The dynamic impedance for Nuclear Power Plant on layered medium is calculated by viscous-spring dynamic artificial boundary model based on harmonic response and the FEM-SBFEM analysis method. By taking different layered interfacial height and soil parameters as example, the numerical comparison is carried out to study the dynamic impendence speciality. The numerical simulation coincides with the numerical solution and the proposed dynamic analysis method is proved to be easily utilized in practical engineering with inhomogeneous soil layers.(2) The time history method is investigated elaborately to solve the earthquake response analysis for nuclear power plant structure. The mode-superposition method is proposed and recommended to solve structure dynamic equation and caculate the floor response spectrum in time domain analysis.(3) Against the reactor building of a 1000MW Nuclear Power Plant structure,the influnce factor for acceleration response spectrum of Nuclear Power Plant is mainly discussed. The influence for the peak acceleration and distribution of the floor response spectrum caused by the change of dynamic shear modulus is mainly investigated in a wide range of foudation shear wave velocity. Sensitivity analysis for poision, damping ratio, density is also carried out.(4) Regular deterministic seismic analysis methods are carried out based on substructure method and direct method to disscuss the influences for the dynamic response of nuclear power plant structure on layered foundation. In the framework of numerical model of lumped parameters, the mode-superposition method and direct integration method based on the dynamic impedance in frequency domain are carried out to solve the dynamic response. It may provide a reliable dynamic analysis model to solve dynamic response to the Nuclear Power Plants on layered foundation. The direct method which foundation model is built by viscous-spring dynamic artificial is carried out to discuss the suitable extent for rigid foundation. The system frequencies and the floor response spectrum of nuclear power plant structure are respectively analysed to study the influenuce caused by layered interfacial height. Conclusions are given that the peak acceleration of floor response spectrum with inhomogeneous soil layers is larger than with homogeneous soil, and the acceleration response spectrum in the vertical direction is more sensitivity. The results of response spectrum indicate the direct method, which foundation model built by setting viscous-spring dynamic artificial, is more sensitivity to reveal the changes with frequency than the lumped parameter foundation model.
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