地震作用下相邻地下结构与土相互作用特性研究

针对简单框架式地铁车站结构的抗震特性研究已取得一定成果,但对于结构形式较复杂或多个地下结构间相互作用等问题仍需进一步探究。本文利用现有地震分析方法中的动力时程分析法对两个地下结构间相互作用的影响进行系统对比分析,其中主体结构为三层三跨车站、附属结构为两层三跨车站。主要探讨附属结构与主体结构间距离的变化、两结构间连接形式对场地土以及主体结构地震响应特性的影响,分析比较场地土变形、主体结构变形、层间位移角以及内力在不同工况下的地震响应特性。结果表明:相邻地下结构与土相互作用形式较独立结构与土相互作用形式对场地土影响更加明显;当附属结构与主体结构间距离超过两倍结构宽度,附属结构对主体结构周围场地变形影响效应可基本忽略;同样当附属结构与主体结构间距离超过两倍的结构宽度,附属结构对主体结构的变形、内力基本已无影响,因此地震情况下相邻结构间相互作用影响范围基本为两倍结构宽度。与此同时,附属结构的存在对于主体结构抗震特性是不利的,不同连接形式中单层通道连接的形式变形以及内力方面均小于双层通道连接形式。

Neighboring Underground Structure-Soil InteractionCharacteristics under Seismic Action

In this paper, the seismic performance of a large subway station with a three-story, three-span major structure, and a two-story, three-span additional structure, was analyzed using a dynamic time-history method. The seismic responses of the site soil and the major structure under varying interaction modes and distances between major and additional structures were discussed. Under different working conditions, deformation of the site soil and the major structure, and the internal force and story drift angle of the major structure were analyzed and compared. Results showed that the influence of the neighboring underground structures-soil interaction on the site soil was more significant than that of the individual underground structures-soil interaction. When the distance between the additional structure and major structure was more than twice the structural width, the effect of the additional structure on the deformation of site soil around the major structure could be neglected, and the effect on the deformation and internal force of the major structure was essentially zero. Hence, the influence range of the interaction between neighboring underground structures under an earthquake was basically twice the structural width. The existence of the additional structure adversely affected the major structure under an earthquake. The deformation and internal force of the structure with a single-layer channel connection were smaller than those with double-channel connections.