土的次非线性对桩基核岛结构三维地震反应的影响  

Influence of soil secondary nonlinearity on 3D seismic responses of a pile-founded nuclear island structure

作　　者：朱升冬 陈国兴[1,2] 陈炜昀 高文生 李文彪[1] ZHU Sheng-dong;CHEN Guo-xing;CHEN Wei-yun;GAO Wen-sheng;LI Wen-biao(Institute of Geotechnical Engineering,Nanjing Tech.University,Nanjing,Jiangsu 210009,China;Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province,Nanjing,Jiangsu 210009,China;School of Civil Engineering,Sun Yat-Sen University,Guangzhou,Guangdong 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]中山大学土木工程学院,广东广州510275 [4]中国建筑科学研究院,北京100013

出　　处：《岩土力学》2023年第5期1501-1511,共11页Rock and Soil Mechanics

基　　金：国家重点研发计划项目(No.2018YFC1504301)。

摘　　要：随着核电厂工程建设快速发展,核电厂选址不可避免地要面临土质场地。土-桩-结构动力相互作用对核岛结构的抗震安全性评价具有重要影响。以国内某拟建的AP1000核岛工程为背景,建立土质场地-群桩-筏板基础-核岛结构动力相互作用体系的3D模型,考虑场址的区域地震环境与历史地震活动性,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。使用一步法和二步法分别实现对土体真非线性和主非线性的模拟,通过对比这两种方法计算的核岛结构地震反应的差异,可知土的次非线性(soil secondary nonlinearity,简称SSN)对核岛结构地震反应的定量影响,也即SSN效应。发现SSN效应对核岛结构水平向地震反应的影响明显大于对竖向地震反应的影响,SSN效应会导致土质场地-群桩-核岛结构体系变得更“柔”;SSN效应与基岩输入地震动的特性强相关,近场中-强地震作用时SSN效应最强;SSN会显著增大核岛结构的峰值加速度和峰值相对位移反应,在核岛结构的抗震设计中不应忽视SSN效应。With the rapid development of nuclear power plant constructions,it has become an unavoidable issue to choose a soil site as the plant site.Soil-pile-structure interaction(SPSI) effect has an important influence on the seismic safety evaluation of a nuclear island structure(NIS).A 3D integrated simulation method is developed to evaluate the seismic responses of a pile-mat-founded AP1000 nuclear-island building system subjected to multidirectional earthquake motions.Considering the regional tectonic setting and historical seismicity around the plant site,a set of three-component recordings for scenarios near-field moderate-strong,moderate-far field strong,and far-field large earthquakes are selected and justified for determining the bedrock shakings used in this study.The whole nonlinearity including both the primary and secondary nonlinearities of soil and only the primary nonlinearity of soil are considered by one-step method and two-step method for performing the 3D response analysis of the SPSI system,respectively.The quantitative influence of soil secondary nonlinearity(SSN) on the NIS seismic responses(i.e.,SSN effect) under earthquake scenarios can be obtained by comparing the results obtained from the above two methods.A finding is that the influences of SSN on the horizontal seismic responses of NIS are obviously greater than those of the vertical ones of NIS,and the SSN effect makes the SPSI system more flexible.The SSN effect is strongly related to the characteristics of bedrock shaking scenarios and is the largest under the near-field moderate-strong earthquake scenarios.Given SSN effect can significantly increase the NIS seismic responses,the SSN effect should not be ignored in the NIS seismic design.

关 键 词：核岛结构 地震反应 土的次非线性 土-桩-结构相互作用 

分 类 号：TU473[建筑科学—结构工程]