变刚度地基上基础隔震结构动力学特性变化规律试验研究  

Test study on dynamic characteristics of base-isolated structure on variable stiffness foundation

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

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

出　　处：《振动与冲击》2023年第7期54-64,76,共12页Journal of Vibration and Shock

基　　金：国家自然科学基金面上项目(51778282)。

摘　　要：基于饱和砂性土地基动孔压比变化对地基刚度的影响规律,通过控制输入地震动持时压缩比和强度的方法,提出了变刚度地基上隔震结构振动台模型试验方法,并结合已完成的不同地基上土-桩-隔震结构系列振动台模型试验,分析了地基刚度变化对基础隔震结构动力学特性的影响规律。结果表明,随着结构-土体相对刚度比的增大,变刚度地基上基础隔震结构一阶自振频率降低,但体系阻尼比明显增大,尤其是隔震层的隔震效率发生了明显的降低。变刚度地基上结构-土体相对刚度比显著影响隔震结构楼层加速度反应和层间位移反应,强震下结构-土体相对刚度比越大,隔震结构楼层加速度反应和层间位移反应较刚性地基时增大越显著。基于系列振动台模型试验结果,初步给出了基于结构-土体相对刚度比的小高宽比隔震结构模型周期延长率、阻尼比、层间位移角SSI影响率以及隔震层位移SSI影响率的预测公式,该研究结果有助于推动结构隔震技术的更广泛应用。Here,based on influence laws of dynamic pore water pressure ratio change of saturated sandy soil foundation on foundation stiffness,a shaking table model test method for isolated structure on variable stiffness foundation was proposed by controlling compression ratio and strength of input ground motion duration.Combined with completed shaking table model tests of soil-pile-isolation structure series on different foundations,influence laws of foundation stiffness change on dynamic characteristics of base-isolated structure were analyzed.The results showed that with increase in relative stiffness ratio of structure-soil body,the first order natural frequency of base-isolated structure on variable stiffness foundation decreases,but system damping ratio increases obviously,especially,the isolation efficiency of isolation layer decreases obviously;relative stiffness ratio of structure-soil body on variable stiffness foundation significantly affects story acceleration responses and inter-story displacement responses of isolation structure,the larger the relative stiffness ratio of structure-soil body under strong earthquakes,the more significant the increases in story acceleration responses and inter-story displacement responses of isolation structure than those on rigid foundation;based on results of a series of shaking table model tests,prediction formulas for period elongation,damping ratio,SSI influence rate of interlayer displacement angle and SSI influence rate of isolation layer displacement of isolated structure model with small aspect ratios based on relative stiffness ratio of structure-soil body are preliminarily deduced;the study results are helpful to promote wider application of structural isolation technology.

关 键 词：变刚度地基 基础隔震结构 振动台试验 动力学特性 隔震效率 

分 类 号：TU311[建筑科学—结构工程]