水平低周往复荷载作用下核岛桩基抗震性能试验研究  

Experimental study on seismic behavior of nuclear-island pile foundation under cyclic lateral loading

作　　者：李斌 景立平[1,2,3] 王友刚 涂健 齐文浩 LI Bin;JING Liping;WANG Yougang;TU Jian;QI Wenhao(Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Engineeringand Engineering Vibration,China Earthquake Administration,Harbin 150080,China;Department of Geological Engineering,Institute ofDisaster Prevention,Sanhe 065201,China;China Nuclear Energy Technology Co.,Ltd.,Beijing 100193,China)

机构地区：[1]中国地震局工程力学研究所,黑龙江哈尔滨150080 [2]中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨150080 [3]防灾科技学院地质工程学院,河北三河065201 [4]中核能源科技有限公司,北京100193

出　　处：《岩土工程学报》2023年第10期2119-2128,共10页Chinese Journal of Geotechnical Engineering

基　　金：中国地震局工程力学研究所基本科研业务费专项项目(2019B10);国家科技重大专项项目(2018ZX06902016)。

摘　　要：群桩基础是核岛结构在非基岩场地采用的主要基础形式,由于核岛结构质量大、刚度大且质量分布集中,会使基桩处于高轴压比的工作状态。为研究高轴压比(轴压比为0.45)钢筋混凝土群桩基础的抗震性能及地震作用下的破坏模式,开展了粉质黏土中钢筋混凝土群桩基础水平低周往复加载试验,分析了桩基的破坏模式和滞回特征以及桩身变形和内力分布等的变化规律。试验结果表明:基桩在桩头区域均发生了压弯破坏,桩头与承台连接部位破坏最为严重,破坏区域延伸至桩顶以下5倍桩径深度范围内;塑性铰埋深的大小关系为推覆前端基桩>推覆后端基桩>边桩>中桩;推覆前端基桩和中桩的桩身弯矩反弯点在桩顶以下(1~3)倍桩径之间,推覆后端基桩有两个反弯点,分别在桩顶以下(3~5)倍和(5~7)倍桩径,边桩没有反弯点;在水平往复荷载作用下桩身挠度呈倒置的“伞”形;弹性工作阶段,推覆前端和推覆后端基桩荷载分配比例均为24%,边桩为21%,中桩为10%。The pile group is the main form of nuclear island structure in non-bedrock site.As the structure of the nuclear island has a large mass,large stiffness and concentrated mass distribution,the piles will have a high axial compression ratio.To study the seismic performance of the pile group with a high axial compression ratio,the cyclic lateral loading tests on the pile group in silty clay are carried out,and the failure mode and hysteretic characteristics as well as the variation law of pile deformation and internal force distribution are analyzed.The test results show that the compression-flexural failure mode occurs at the pile head,the connection between pile head and cap is the most serious,and the failure area extends to the depth of 5 times the pile diameter below the pile top.The relationship of plastic hinge length is as follows:front pile back pile side pile middle pile.The inflection points of the front pile and the middle pile are between 1D and 3D below the pile top.The back pile has two inflection points,which are respectively between 3D~5D and 5d~7d below the pile top.The side pile has no inflection point.The deflection of the pile presents an inverted umbrella shape.At the elastic working stage,the load distribution proportion of the front pile and back pile is 24%,that of the side pile is 21%,and that of the middle pile is 10%.

关 键 词：核岛 群桩 高轴压比 水平往复加载 抗震性能 

分 类 号：TU473[建筑科学—结构工程]