地震动持时压缩比对可液化地基地震反应影响的振动台试验  

Shaking table test on effects of ground motion duration compression ratio on seismic response of liquefied foundation

作　　者：许成顺[1] 豆鹏飞 高畄成 陈苏[2] 杜修力[1] XU Cheng-shun;DOU Peng-fei;GAO Liu-cheng;CHEN Su;DU Xiu-li(The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]中国地震局地球物理研究所,北京100081

出　　处：《岩土力学》2019年第1期147-155,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金创新研究群体项目(No.51421005);国家自然科学基金项目(No.51578026)~~

摘　　要：在与可液化场地相关的振动台模型试验中,地震动持时按照时间相似比压缩后,所输入地震动的持时、频率、能量等特性均发生改变,这将对液化地基在地震荷载下的动力响应产生显著影响。以持时压缩比例为研究的唯一变量,依托小型振动台试验,分析了各组试验中可液化地基土在地震中的宏观现象、加速度反应、孔压比发展等,针对与可液化场地相关振动台试验设计中的地震动持时按照时间相似比压缩后对液化场地动力响应影响的问题进行研究。试验结果表明:地震动记录按照很小的相似比压缩后持时太短,地震动峰值一定时,可液化场地则有可能不发生液化;地震动持时越长,地震动能量越大,超孔隙水压力随地震动的输入积累迅速,场地土液化现象越明显,土体中加速度反应也表现出不同规律。根据得到的试验结果,建议在涉及可液化场地的振动台模型试验中,所输入的地震记录采用原始持时地震动记录或按照较大时间相似比压缩的地震动记录。In the shaking table model test on liquefiable sandy soil, the duration, frequency, energy and other characteristics of ground motion have changed after the seismic record time is compressed according to the time similarity ratio, and it will have a significant impact on the dynamic response of liquefiable foundation under seismic loading. The time compression ratio is the only variable in this series of shaking table model tests, and the effects are analysed by the characteristics, such as macroscopic phenomena, acceleration, pore water pressure. The effect of dynamic response of liquefied site in the shaking table tests with seismic record after time holding compression is researched in this paper. Results show that when the PGA of the input ground motion is similar, liquefied site may not be liquefied if the seismic record time is compressed. The longer the duration, and the greater the energy of the ground motion, excess pore water pressure accumulates rapidly, and the phenomenon of soil liquefaction and the filter isolation effects are obvious. According to the results of the tests, it is suggested that the original ground motion could be directly adopted by the shaking table tests regarding liquefaction as research objective.

关 键 词：地震动持时压缩 振动台模型试验 加速度 液化 

分 类 号：TU435[建筑科学—岩土工程]