The number of traditionally excellent coastal lithologic nuclear power plants is limited. It is a trend to develop nuclear power plants on soil sites in inland areas. Therefore, the seismic safety and adaptability of non-rock nuclear power plant (NPP) sites are the key concerns of nuclear safety researchers. Although the five site categories are clearly defined in the AP1000 design control documents, the effects of nuclear power five site conditions and soil nonlinearity on the seismic response characteristics of nuclear island buildings have not been systematically considered in previous related studies. In this study, targeting the AP1000 nuclear island structure as the research object, three-dimensional finite element models of a nuclear island structure at five types of sites (firm rock site (FR), soft rock site (SR), soft-to-medium soil site (SMS), upper bound soft-to-medium site (SMS-UB), and soft soil site (SS)) are established. The partitioned analysis method of soil-structure interaction (PASSI) in the time-domain is used to investigate the effects of site hardness and nonlinearity on the acceleration, displacement, and acceleration response spectrum of the nuclear island structure under seismic excitation. The incremental equilibrium equation and explicit decoupling method are used to analyze the soil nonlinearity described by the Davidenkov model with simplified loading-reloading rules. The results show that, in the linear case, with the increase of site hardness, the peak ground acceleration (PGA) and the peak of acceleration response spectrum of the nuclear island structure increase except for the FR site, while the maximum displacement decreases. In nonlinear analysis, as the site hardness increases, the PGA, maximum displacement, and the peak of acceleration response spectrum of the nuclear island structure increase. The peak value of the acceleration response spectrum in the nonlinear case is greater than that in the linear case for FR, while smaller for SR and soil sites. The site nonlinearity reduces the peak values of the response spectrum for SR and soil sites much more as the site hardness decreases. The results of this study can provide a reference for design of nuclear island structures on soil and rock sites.

传统上优秀的沿海岩性核电站数量有限。在内陆地区的土壤场地上发展核电站是一种趋势。因此，非岩石核电站（NPP）场址的抗震安全性和适应性是核安全研究人员关注的重点。虽然在AP1000设计控制文件中明确定义了五种场地类别，但以往的相关研究并未系统地考虑核电五种场地条件和土壤非线性对核岛建筑地震响应特性的影响。本研究以AP1000核岛结构为研究对象，建立五类场地（硬岩场地（FR）、软岩场地（SR）、建立了软土场地（SMS）、上界软土场地（SMS-UB）和软土场地（SS）。采用时域土-结构相互作用（PASSI）分区分析方法，研究了场地硬度和非线性对核岛结构在地震激励下的加速度、位移和加速度响应谱的影响。增量平衡方程和显式解耦方法用于分析由简化加载-重载规则的 Davidenkov 模型描述的土壤非线性。结果表明，在线性情况下，随着场地硬度的增加，除FR场地外，核岛结构的峰值地面加速度（PGA）和加速度响应谱峰值均增加，而最大位移减小。在非线性分析中，随着场地硬度的增加，核岛结构的PGA、最大位移和加速度响应谱峰值增加。FR 非线性情况下的加速度响应谱峰值大于线性情况下的加速度响应谱峰值，而 SR 和土壤场地的加速度响应谱峰值较小。随着场地硬度的降低，场地非线性降低了 SR 和土壤场地响应谱的峰值。该研究成果可为土石场地核岛结构设计提供参考。FR 非线性情况下的加速度响应谱峰值大于线性情况下的加速度响应谱峰值，而 SR 和土壤场地的加速度响应谱峰值较小。随着场地硬度的降低，场地非线性降低了 SR 和土壤场地响应谱的峰值。该研究成果可为土石场地核岛结构设计提供参考。FR 非线性情况下的加速度响应谱峰值大于线性情况下的加速度响应谱峰值，而 SR 和土壤场地的加速度响应谱峰值较小。随着场地硬度的降低，场地非线性降低了 SR 和土壤场地响应谱的峰值。该研究成果可为土石场地核岛结构设计提供参考。