基于振动台试验的平行隧道近距离下穿地铁车站结构地震响应研究

Shaking table test on the seismic response of parallel tunnels closely crossing beneath a subway station

目前对于单一地下结构抗震性能的研究十分丰富,而相互穿越地下结构体系在地震时的相互作用机理和影响规律的研究还不够成熟。基于1g振动台试验,探究近距离隧道平行下穿车站体系对场地土以及地下结构之间的影响规律。对比分析表明:(1)地下结构的存在可降低地表加速度响应,最大降低幅度可达25%;(2)上部车站的存在可以降低下穿隧道的加速度响应,最大降低幅度可达25%,而下穿隧道对上部车站加速度响应的影响则相对复杂,没有体现出一般规律性;(3)地下结构的加入对体系动力特性(主要是基频)的影响十分有限,从工程应用的角度可不予考虑。研究成果可为地下结构穿越体系的地震响应分析和初步设计提供参考。

The seismic performance of underground structure systems is extensively studied,but research on the interaction mechanism and influence law of underground structure crossing systems during an earthquake is limited.In this study,the influences of parallel tunnels crossing beneath a subway station system on the site soil and the underground structure were investigated with a 1 g shaking table test.Test results show that(1)the underground structure would reduce the surface acceleration response by up to 25%;(2)the upper station would reduce the acceleration response of the underpass tunnels by up to 25%,and the influence of the underpass tunnels on the acceleration response of the upper station is complex and has no general regularity;(3)the influence of the underground structure on the dynamic characteristics(mainly the fundamental frequency)of the system is extremely limited and can be ignored in practical engineering.The research results could provide a reference for the seismic response analysis and preliminary design of the underground structure of a crossing system.