两种岩土隔震系统的振动台试验研究

Shaking table tests on two geotechnical seismic isolation systems

采用低成本的减隔震技术是降低农村房屋地震灾害的重要途经。近年来,围绕结构基础与地基土之间使用低模量材料的岩土隔震技术(GSI)引起了广泛的研究兴趣。提出了两种低成本的岩土隔震系统即基于砂垫层的岩土隔震系统(GSI-SC)和基于玻璃珠-砂垫层的岩土隔震系统(GSI-GBSC)。通过考虑场地的大比例振动台模型试验对单层砌体结构模型进行了有、无隔震系统的对比试验,单层砌体结构模型采用1/4的缩尺比例制作。选取1940年记录到的El-Centro波南北分量作为输入波,输入加速度幅值分别为0.1g,0.2g,0.4g。振动台试验结果表明:提出的两种低成本的岩土隔震系统均可以减少结构的地震反应,达到隔震的目的;在输入加速度幅值为0.4g时,GSI-SC系统使结构屋面板的加速度反应以及结构的层间位移反应的减小率分别达到33%和39%;而GSI-GBSC系统相应的减小率更是达到了45%和48%。GSI-SC系统和GSI-GBSC系统都具有良好的隔震效果,且施工简便、成本低廉,适合在农村地区推广。就隔震效果而言,GSI-GBSC系统较GSI-SC系统更具有优势。

Applying the low-cost seismic isolation technology is a key way to reduce earthquake disasters of rural houses.Recently,the geotechnical seismic isolation(GSI)which uses low modulus materials between the structural foundation and the foundation soil has aroused widespread research interest.In this study,two low-cost GSI systems are proposed,which include the geotechnical seismic isolation system based on the sand cushion(GSI-SC)and the geotechnical seismic isolation system based on glass bead-sand cushion(GSI-GBSC).Through the large-scale shaking table model tests considering the site,the comparison tests between the single-layer masonry structure model with and without isolation system are carried out.The single-layer masonry structure model is made with a 1/4 scale.The north-south component of the El-Centro waves recorded in 1940 is selected as the input waves,and the peak input acceleration is 0.1g,0.2g,and 0.4g,respectively.The results of the shaking table tests show that the two proposed low-cost GSI systems can decrease the seismic response of the structures and achieve the purpose of isolation.When the input acceleration amplitude is 0.4g,the GSI-SC system makes the reduction rate of the acceleration response of the structural roofs and the interlayer displacement response of the structures reach 33%and 39%,respectively,while the corresponding reduction rate of the GSI-GBSC system is 45%and 48%.Both the GSI-SC system and the GSI-GBSC system have strong isolation capability,simple construction and low cost,which are suitable for promotion in rural areas.In terms of isolation effect,the GSI-GBSC system has more superiority to the GSI-SC system.