Abstract The influence analysis of the site condition is a key issue considered in the seismic design of nuclear power engineering on non-rock sites. To study the soil–structure interaction (SSI) effect of the site conditions on the structural seismic response of nuclear power engineering, we used a CAP1400 nuclear power plant as a case study subject and performed a shake table testing of a soil–structure system model. The test results indicate that there are strong nonlinear effects of non-rock site, that is, with increase of seismic input level (peak ground acceleration, PGA), the natural vibration frequency of the soil-structure system decreased significantly, and the damping ratio increased; Under all seismic input levels, the site amplification phenomena occurred in different directions, and the response accelerations of soil and structure in the high-frequency range (>3 Hz) are greatly influenced by the SSI effect; The cracks began to appear in the model soil under lower seismic input level (PGA 0.20 g) and developed, lengthen and widen under the high seismic input level (PGA≥0.30 g), and the soil cracks were almost all connected under the SME seismic input level (PGA 0.51 g), but still no micro-cracks were detected on the model structure; Under the SSE seismic input level (PGA 0.30 g) the contact surface separation appeared on the contact surfaces of the model soil and the structure foundation, and then under the ultra SME seismic input level (PGA 0.84 g) the structure foundation became unbalanced so that the soil-structure system failed. The influence of the site conditions on the seismic response of the structure was significant. The seismic response analysis and seismic design of the nuclear island structure on no-rock sites should take into account the effects of site conditions and soil-structure interaction.

中文翻译：

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非岩石场地核电厂土-结构体系振动台试验分析

摘要 场地条件的影响分析是核电工程无岩场地抗震设计中考虑的关键问题。为了研究场地条件对核电工程结构地震响应的土-结构相互作用（SSI）影响，我们以 CAP1400 核电站为案例研究对象，并对土-结构系统模型进行了振动台试验. 试验结果表明，非岩石场地存在较强的非线性效应，即随着地震输入水平（峰值地面加速度，PGA）的增加，土-结构体系的自振频率显着降低，阻尼比增加; 在所有地震输入水平下，场地放大现象发生在不同方向，土体和结构在高频范围（>3Hz）的响应加速度受SSI效应影响较大；模型土体在较低地震输入水平（PGA 0.20 g）下开始出现裂缝，并在高地震输入水平（PGA≥0.30 g）下发展、加长和加宽，在SME地震作用下土体裂缝几乎全部连通。输入水平（PGA 0.51 g），但在模型结构上仍然没有检测到微裂纹；在SSE地震输入水平（PGA 0.30 g）下，模型土与结构地基的接触面出现接触面分离，然后在超SME地震输入水平（PGA 0.84 g）下，结构地基变得不平衡，使得土壤结构系统失败了。场地条件对结构地震反应的影响是显着的。无岩场地核岛结构的地震响应分析和抗震设计应考虑场地条件和土-结构相互作用的影响。