可液化地基上桩基基础小高宽比隔震结构体系振动特性试验研究  

Experimental research on vibration characteristics of small height-width ratio isolation structure system of pile foundation on liquefiable foundation

作　　者：于旭[1,2] 赵畅 庄海洋[2,3] 陈国兴 YU Xu;ZHAO Chang;ZHUANG Hai-yang;CHEN Guo-xing(School of Civil Engineering and Architecture,Nanjing Institute of Technology,Nanjing 211167,China;Institute of Geotechnical Engineering,Nanjing Tech University,Nanjing 210009,China;School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]南京工程学院建筑工程学院,江苏南京211167 [2]南京工业大学岩土工程研究所,江苏南京210009 [3]华东交通大学土木建筑学院,江西南昌330013

出　　处：《振动工程学报》2023年第4期1125-1135,共11页Journal of Vibration Engineering

基　　金：国家自然科学基金面上项目(51778282,51978333)。

摘　　要：为研究地基液化对小高宽比隔震结构体系振动特性的影响,通过振动台模型试验再现了桩基基础小高宽比隔震结构体系在液化场地上的地震反应过程,分析了地基液化过程中基础及隔震层振动特性和隔震结构地震响应规律。结果表明:地基液化后小高宽比隔震结构的一阶自振频率较刚性地基时大幅增加,阻尼比较刚性地基时也明显增加;液化地基上隔震层对群桩基础水平向加速度反应起明显的放大作用,隔震效能消失,但隔震层对桩基承台转动角加速度反应起显著的减震作用;液化地基上小高宽比隔震结构楼层加速度峰值放大系数的分布规律与非液化地基上隔震结构相比也具有明显差异,呈现出弯曲放大的特点,隔震结构顶层加速度峰值放大系数增大尤为明显;液化地基上小高宽比隔震结构的最大层间位移反应远超刚性地基上隔震结构在强震作用下的最大层间位移反应,可能导致基于刚性地基假定设计的隔震结构在地基液化时不满足抗震设计要求。In order to study the effect of foundation liquefaction on the vibration characteristics of a small height-width ratio isolation structure system,the seismic response process of a small height-width ratio isolation structure system of pile foundation on liquefac⁃tion site is reconstructed by shaking table model test.The seismic response of the isolated structure during the process of soil lique⁃faction is analyzed.The results show that:the first natural frequency of the isolated structure on the liquefiable soil foundation is significantly higher than that on the rigid foundation,and the damping ratio is also significantly higher than that on the rigid founda⁃tion.The isolation layer on the liquefiable soil foundation plays a significant role in amplifying the horizontal acceleration response of the pile foundation,and the isolation effect disappears.However,the isolation layer plays another significant role in reducing the rotational angular acceleration response of the pile foundation.The distribution law of the peak acceleration amplification factor of the floor of small height-width ratio isolation structures on the liquefiable soil foundation is obviously different from that on the nonliquefaction foundation,which shows the characteristics of bending amplification,and the amplification coefficient of peak accelera⁃tion on the top floor of the isolation structure increases obviously.The maximum inter⁃storey displacement response of isolated structures on the liquefiable soil foundation is far greater than that on the rigid foundation under strong earthquake action,which may lead to the isolation structures based on the assumption of the rigid foundation not meeting the requirements of seismic design when the soil foundation liquefies.

关 键 词：隔震结构 振动台试验 液化地基 动力特性 地震反应 

分 类 号：TU311[建筑科学—结构工程]