考虑土体非线性的核岛结构桩基础三维地震反应特性  

3D seismic response characteristics of piles of a nuclear island building considering nonlinearity of soil

作　　者：朱升冬 陈国兴[1,2] 陈炜昀 高文生 Zhu Shengdong;Chen Guoxing;Chen Weiyun;Gao Wensheng(Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 210009,China;Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province,Nanjing 210009,China;Sun Yat-Sen University,Guangzhou 510275,China;China Academy of Building Research,Beijing 100013,China)

机构地区：[1]南京工业大学岩土工程研究所,江苏南京210009 [2]江苏省土木工程防震技术研究中心,江苏南京210009 [3]中山大学,广东广州510275 [4]中国建筑科学研究院,北京100013

出　　处：《土木工程学报》2023年第11期124-136,共13页China Civil Engineering Journal

基　　金：国家重点研发计划项目(2018YFC1504301)。

摘　　要：以某沿海拟建的AP1000核岛结构为背景,用3D集中质量-梁杆模型模拟核岛结构,考虑土体的非线性滞回特性,建立非均匀地基-群桩-厚筏-核岛结构体系的3D有限元模型,选用近场中强震、中-远场强震和远场大地震的三分量记录作为基岩输入地震动,分析群桩基础的地震反应特性。非线性场地效应和土-桩-结构动力相互作用效应的耦合作用会显著增大核岛结构的基础输入运动,不论基准运行地震或安全停堆地震,基础输入运动的水平向和竖向上包络加速度反应谱(5%阻尼比)的谱值显著大于对应的AP1000标准设计反应谱谱值;桩顶累积绝对速度和地震峰值内力的大小受基岩输入地震动特性的影响显著,与场地反应的非线性程度正相关,其复杂的空间分布特征也受土-桩-结构动力相互作用效应和桩的几何布置的综合影响,桩-筏交界处的桩身地震内力反应最大,中-远场和远场强震作用对核岛桩基础的潜在破坏风险可能远大于近场中强地震作用。Based on a proposed coastal AP1000 nuclear island structure(NIS),a 3D lumped mass⁃stick(LMS)model was applied to simulating the AP1000 NIS considering the nonlinear hysteretic characteristics of soil.Furthermore,a 3D finite element model of the inhomogeneous site⁃piles⁃AP1000 NIS system was established.This work presents results from a comprehensive simulation study on the seismic response of piles under the NIS subjected to near⁃field moderate⁃strong earthquake,moderate⁃far field strong earthquake,and far⁃field large earthquake scenarios.The combination of the nonlinear site effect and soil⁃pile⁃structure dynamic interaction(SPSI)effect may significantly increases the foundation input motions(FIMs)of the AP1000 NIS.As for the ultimate safety earthquake(SL⁃2 level)or the operational safety earthquake(SL⁃1 level),the upper envelopes of the 5%damping horizontal and vertical spectral accelerations of the FIMs at the SL⁃1 and SL⁃2 levels are significantly larger than those of the corresponding AP1000 standard response spectra.Under earthquake scenarios,the magnitudes of the cumulative absolute velocity and the peak seismic internal forces at the top of piles correlates positively with the degree of site nonlinearity and are strongly affected by the characteristics of input bedrock motions.The complex spatial distributions are significantly influenced by the coupling effect of the SPSI effect and the pile layout.The maximum values of the peak seismic internal forces of piles may occur at the pile⁃base mat.The moderate⁃far field and far⁃field strong motion scenarios with low⁃frequency components and long durations have a greater risk of damaging the piles under the NIS than the near⁃field strong motion scenario.

关 键 词：桩基础 核岛结构 土-桩-结构动力相互作用 土的非线性 地震反应 

分 类 号：TU311.3[建筑科学—结构工程] TU473.1[电气工程—电力系统及自动化] TM623