Nonlinear seismic responses of the soft rock site for nuclear power plants

Abstract

With the development of the nuclear power industry, high-quality bedrock nuclear power stations have become scarce. Thus, it is inevitable that nuclear power stations will be built on soft rock sites. This involves the issue of the seismic safety of soft rocks as sites for nuclear power plants. Based on the soft rock site involved in the site selection for nuclear power plants, this paper uses ground motions with different spectral characteristics. Using the DEEPSOIL software for soil layer analysis and the Abaqus finite element software, one-dimensional equivalent linear and nonlinear methods are employed to compare and analyze the characteristics of the nonlinear seismic response of the soft rock site for nuclear power plants. The soft rock site has a significant amplification effect on the input ground motion. The equivalent linear and nonlinear methods have different levels of influence on the acceleration response of the soft rock site. Under the action of far-field earthquakes, surface acceleration and its response spectrum, which were calculated using the abovementioned methods, are relatively close. As the input ground motion intensity increases, the nonlinearity of the soft rock increases, and the amplification effect of the soft rock site weakens. However, the peak ground acceleration of the surface obtained using the two methods gradually differs. Moreover, the nonlinearity is greater than the equivalent linear. Therefore, the nonlinear characteristics of soft rocks should be considered in the site selection and seismic analysis of nuclear power plants.