LARGE-SCALE SHAKING TABLE TEST FOR SEISMIC RESPONSE IN PORTAL SECTION OF GALONGLA TUNNEL
(1. China Merchants Chongqing Communications Research and Design Institute Co.,Ltd.,Chongqing 400067,China;2. Chongqing Institute of Coal Science Institute,Chongqing 400037,China;3. Chongqing Jiaotong University,Chongqing 400074,China)
Abstract:As the key position of tunnel seismic design,the portal section is extremely vulnerable to foundation failure and structure damage. The longitudinal distances of 100 m in portal section of Galongla tunnel are selected as the prototype to conduct large-scale shaking table test. The research results are shown as follows:(1) The soil around tunnel has obvious amplification effect on the input seismic waves with the frequency near the predomination frequency of soil;and also it has filtering effect on the input seismic waves with high frequency. (2) The tunnel vibrates synchronously with the surrounding soil;and it doesn?t show its own natural vibration frequency. The inertial force has little effect on underground structure?s seismic response. So the key point of tunnel?s anti-seismic research is failure prevention of surrounding rock under the earthquake;and the main purpose of structure?s aseismic design is to reduce the structure damage from the failure of its surrounding rock. (3) The absorbers and aseismatic joints don?t change the spectrum characteristics of lining;but they can increase the peak acceleration of lining. So,the damping effect should not be judged by the acceleration magnified coefficient at these places. The research results have important application value to aseismic design and shock absorption design of tunnel.
蒋树屏. “主动洞”的减震作用研究[C]//中国科协第十一届年会19分会场论文集. 北京:人民交通出版社,2009:447-454.(JIANG Shuping. Study of damping effect based on“voluntary tunnel”[C]// Proceedings of the 19th Session of the Eleventh Annual Meeting of China Association for Science. Beijing:China Communications Press,2009:447-454.(in Chinese))
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