【摘要】 针对软弱粉质黏土场地条件的三跨三层地铁车站结构,进行近远场地震动作用下土-地下结构动力相互作用振动台模型试验,测试地铁车站结构的加速度、应变反应、水平位移反应和地基土的加速度、震陷及其作用于侧墙的动土压力反应。分析软弱场地土的近远场加速度反应规律、地表震陷特征,结果表明:近、远场地震动作用下,地基土的地震动频谱均呈现出低频放大现象,但其放大效应的程度和频率范围差异较大;由于强地震动作用下地基土发生软化,地基土的地震动频谱特性体现出明显的集中效应;强地震动作用时地基土的基频与远场地震动的主频接近,地基土的地震动放大效应更为显著;地表震陷随输入地震动峰值加速度的增大而增大,但地铁车站结构与土层的竖向相对滑动较小。更多还原

【Abstract】 According to a subway station structure of three stories and three spans in soft silty clay site,a series of shaking table tests on the dynamic interaction between soil and underground structures under both near and far field ground motion are conducted.In this test,parameters such as acceleration,horizontal displacement,strain response of the station,and the pore water pressure,acceleration,seismic subsidence of soil and dynamic soil pressure on the sidewall are measured.This paper mainly analyzes the acceleration of soil under both near and far field ground motion,also studies the characteristics of the seismic subsidence.The results show that the the frequency spectrum of soils present a amplification phenomenon with low frequency under near and far field motions,however,the degree of amplification effect and frequency range appear to be a great difference.Moreover,the soil softening occurs under strong earthquake and then the spectrum reflects a significant concentration effect.Besides,when it comes to the far-field motions,the values of soil’s baseband are approximately equal to the basic frequency of the strong motion,so the amplification effect of the soil seems more significant.In addition,the surface subsidence becomes more serious with the increasing input peak acceleration,while the vertical relative movement between the station structure and soils seems not so obvious.更多还原