上部结构与地基相对刚度比对土-结构体系基频影响试验研究  

Experimental investigation on the effect of the relative stiffness ratio between superstructure and ground soil on the fundamental frequency of soil-structure system

作　　者：尚守平[1] 贺志文[1,2] 王海东[1] 刘方成[1] 熊伟[1] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南省建筑设计院,湖南长沙410001

出　　处：《地震工程与工程振动》2008年第5期94-101,共8页Earthquake Engineering and Engineering Dynamics

基　　金：湖南省科技厅科技计划重点项目(06sk4057);国家自然科学基金项目(5057806250278033);教育部博士点基金新教师项目(20070532090)

摘　　要：本文进行了室内刚性地基上和土槽中1:4钢框架模型的顶部牵引释放试验。对采集的信号进行频谱分析,得到不同刚度时刚性地基上钢框架模型的基频和土槽中土-结构体系的基频。比较钢框架在土槽中的基频和在刚性地基上的基频,发现土-结构动力相互作用(SSI)使土-结构体系基频降低,基频折减率最大为29.37%,且基频折减率与上部结构与地基相对刚度比有关,相对刚度比越大,折减率越大。根据试验结果得出钢框架模型基频折减率随上部结构与地基相对刚度比变化拟合公式。本文试验结果还表明即使在Ⅱ类场地上的结构,当上部结构与地基刚度比较大时有必要考虑土-结构动力相互作用。Free vibration experiment with initial displacement in a steel frame model on the scale of 1：4 were conducted on the rigid ground and on the soil-trough in door, respectively. After analyzing the spectra of the signals acquired, fundamental frequencies of the steel frame on the rigid ground and on the soil-trough in different stiffness were obtained, respectively. Compared with the fundamental frequencies of the steel frame on the rigid ground, the fundamental frequencies of the steel frame on the soil-trough decrease obviously due to the effect of the soil-structure interaction （SSI）. The maximum discount of the fundamental frequencies is 29.37%, and the discount of fundamental frequencies has a close relationship with the relative stiffness ratio of superstructure to ground soil and it increases with the relative stiffness ratio. An expression of the change of the fundamental frequency discount versus the relative stiffness ratio was also obtained by data fitting. The experiment results of the paper also indicate that if the structure is on the classⅡsite and the relative stiffness ratio is large, it is necessary to take SSI into consideration.

关 键 词：土-结构动力相互作用 牵引释放试验 基频折减率 相对刚度比 

分 类 号：P315.983[天文地球—地震学]