地铁运行对国家大型地震工程模拟研究设施的振动影响分析

Analysis of the vibration effects of metro operation on the national facility for earthquake engineering simulation

天津地铁6号线紧邻天津大学北洋园校区,列车运行可能会对学校重要建(构)筑物产生不利振动影响。本文以距该线路较近的天津大学国家大型地震工程模拟研究设施为研究对象,对沿线场地以及设施建(构)筑物进行现场振动测试,研究了振动沿场地的衰减规律和设施建(构)筑物内振动控制点的振动水平;建立了隧道-场地-设施建(构)筑物整体有限元模型,开展了有/无河道(实际存在河道)情况下,场地以及设施建(构)筑物振动仿真模拟分析,着重探讨了河道对场地和设施建(构)筑物的隔振情况。研究表明,由于天津软土场地及河道的影响,场地竖向加速度衰减显著,0~80 m衰减达97.33%;设施的大体积混凝土基础及其底部桩基设计有利于基础自身的振动控制;河道使得场地和设施大型振动台基础的加速度振幅分别降低40.87%和27.97%,场地频谱在0~20 Hz和40~70 Hz区间出现明显的“双峰”现象。

Tianjin Metro Line 6 is adjacent to Beiyangyuan Campus of Tianjin University,and the train operation may cause adverse vibration effects on important infrastructures of the campus.In this paper,the National Facility for Earthquake Engineering Simulation of Tianjin University,which is close to the line,is taken as the research object.Firstly,the site vibration test is carried out on the sites distributed along the line and the adjacent constructions,through which the vibration attenuation law along the site and the vibration level of the control points in the constructions are studied.Furthermore,a whole process finite element model of tunneling-site-facility constructions is established,and the vibration simulation analysis of site and facility constructions is carried out considering whether the protected river exists or not(actually there is a protected river).The vibration isolation efficiency of the protected river is emphatically discussed.The research shows that the vibration impact of the operation of Tianjin Metro Line 6 on the large-scale earthquake engineering simulation research facilities of Tianjin University meets the limit requirements of the code.Affected by Tianjin soft soil and the protected river,the vertical acceleration attenuation of the site is significant,and the attenuation rate reaches 97.33%from 0m to 80 m.The design of the mass concrete foundation of the facility and its bottom pile foundation is helpful to the vibration control of the foundation itself.Due to the presence of protected river,the amplitude of the site and the large shaking table foundations was reduced by 40.87%and 27.97%,and the frequency spectrum of the site showed obvious“double peak”phenomenon in 0~20 Hz and 40~80 Hz bands.