Seismic Response Analysis of Pile Foundation of an Underground Storage Facility of Nuclear Power Project

Abstract

Abstract The proposed site condition of an underground storage facility of nuclear power project (NPP) is complex, characterized by strong spatial variability of bedrock surface, non-uniform soil layers and underlying soft soil. If the substructure method commonly used in nuclear power engineering seismic analysis is adopted, the non-homogeneous foundation must be simplified as the horizontal layered site condition. Therefore, the dynamic interaction features among piles, foundation soil and superstructures under strong earthquakes cannot be reflected accurately. Taking it as the project background, this paper conducts a research on the three-dimensional time-history seismic analysis method for NPPs. On the theoretical basis of viscoelastic artificial boundary and wave equation method, the soil-structure dynamic interaction analysis methodology in complicated non-homogeneous site is put forward in this paper, which is called the integral time-domain method. And an efficient platform is set up for computing artificial boundary parameters and seismic motions. Then the seismic response analysis of pile foundation of the underground storage facility is completed. It is concluded that the pile-soil-structure interaction does not affect horizontal response of the super structure significantly but leads to a frequency shift of the response peak in vertical direction. Additionally, the substructure method is used to verify the accuracy of the proposed method and the results of two methods match well. In conclusion, the integral time-domain method contributes to appropriately simulating the foundation radiation damping and seismic input. It has high accuracy and applicability. The research method and the computing platform can be taken as technical references for seismic response analysis of NPPs constructed in non-horizontal layered foundation or complex geologic bodies conditions.