Abstract With the rapid development of nuclear industry in China, an increasing number of nuclear power plants (NPPs) are unavoidable to be constructed upon non-lithological foundations. Therefore, it is essential to optimize the current evaluation methods for non-lithological foundation reinforcement plans. By using the Octree discretization method combining with the scaled boundary polyhedron finite element method (SBFEM), a refined calculation model of a Generation III+ NPP is constructed. Due to the highly nonlinear dynamic characteristics of the system involved, this paper adopts a generalized plasticity model for the soil, a plastic damage model for the piles, and a nonlinear overburden layer-based seismic input method. Subsequently, large scale plastic damage analysis in detail to the NPPs under beyond-design basis earthquake inputs is performed. The results show that the pile foundation damage characteristics and distribution acquired from simulations agree well with the data from actual earthquake disasters. The most severe damage to the pile foundation occurred at the interface between the end of the pile and the base mat. The inclusion of plastic damage showed that the floor response spectra of the nuclear island experiences significant changes in three dimensions. Therefore, the effect of pile damage to the dynamic response of the power plants should be considered for strong earthquake excitation. The computational and analysis methods proposed in this paper can effectively reflect the dynamic nonlinear response of the nuclear power plants pile foundation-soil interaction.

中文翻译：

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超设计基准地震激发下核电站桩基塑性损伤分析

摘要 随着我国核工业的快速发展，越来越多的核电站（NPPs）不可避免地要建在非岩性地基上。因此，对现有非岩性地基加固方案的评价方法进行优化是十分必要的。采用八叉树离散化方法结合标度边界多面体有限元法（SBFEM），构建了三代+核电厂的精细化计算模型。由于所涉及系统的高度非线性动力特性，本文采用了土体的广义塑性模型、桩体的塑性损伤模型和非线性上覆层地震输入法。随后，在超设计基准地震输入下，对核电厂进行了详细的大规模塑性损伤分析。结果表明，模拟得到的桩基损伤特征及分布与实际地震灾害数据吻合较好。桩基损坏最严重的部位发生在桩端与基垫之间的界面处。包括塑性损伤表明，核岛的地板响应谱在三个维度上发生了显着变化。因此，强震激发时应考虑桩身破坏对电厂动力响应的影响。