复合开挖方式下地铁车站深基坑变形规律研究

随着城市现代化程度的不断深入,城市地铁车站的建设所面临的周边环境也越来越复杂,仅仅依靠某一种单一的施工模式,已经很难适用于当前的工程需求。本文以武汉地铁二号线街道口车站与下穿通道的深基坑工程为研究背景,依托该场地复杂的环境条件,地铁车站采用了明挖法与盖挖法相结合的施工方法。依据基坑的开挖以及围护结构的设计方案,制定了深基坑变形监测方案,对街道口车站在施工期间围护结构的变形情况进行了系统监测,对围护结构在复合开挖方式下的变形规律进行了研究。研究结果表明,盖挖法能够较好地控制围护结构所产生的侧向变形,基坑开挖具有显著的时空效应,在基坑开挖期间应及时架设钢支撑,减小基坑侧壁在无支撑情况下的暴露时间。

Research on deformation of the subway deep foundation pit under complex excavation case

With deepening of urban modernization, the construction of urban subway station is facing more and more complex surrounding environment conditions. A single construction mode for deep foundation pit is difficult to fit the current project needs. This paper presents deformation monitoring results when the open cut method combined with cover-excavation method are used in the construction of deep foundation pit of Jiedaokou Station, where is the underpasses tunnel of Wuhan subway No. 2 lines. The surveying plan of deformation monitoring of the deep foundation pit is proposed. Based on the monitoring data, the deformation characters of the retaining structure under complex excavation method are concluded. The results show that cover-excavation method can better control the lateral displacement of retaining structure, and deep foundation pit excavation has significant time-space effects. During excavation, we should set up steel braces timely and decrease exposure time of the side wall without support.