地铁竖井施工过程中周边环境响应分析

RESPONSE OF SURROUNDING ENVIRONMENT DURING EXCAVATING OF SUBWAY SHAFT ADJACENT TO BUILDING

为明晰地铁竖井施工过程中周边场地的响应,减少地铁施工风险,以长春地铁1号线自由大路车站竖井工程为背景,采用有限元软件对竖井周围场地及邻近建筑物沉降进行数值模拟。探讨了倒挂井壁法竖井施工过程中周围场地地表变形特点和机理,分析了工程中隔离排桩的作用。研究表明:衬砌水平变形与井底隆起变形是竖井开挖引起周围地层变形移动的主要原因;设置的隔离排桩阻断了上部地基的变形传递,降低了竖井开挖施工对周边建筑物地基的累积沉降及差异沉降量的影响。最后,对隔离排桩桩长设置进行了探讨。研究成果对类似相关工程的设计与施工具有借鉴意义。

Many engineering cases show that the risks of the circumstances around the metro station caused by the excavation of these accessory structures including shaft,cross channel,and metro station pilot tunnel are the major component of the metro construction risk. This paper aims to comprehend the response of surrounding area during the construction of subway shaft. It is based on a subway shaft engineering project of the Changchun subway line 1.The shaft is located at the crossings of Ziyou Road and Renmin Street of Changchun city. Settlements of the surface and adjacent buildings around shaft are studied using finite element software and field monitoring data. The ground surface deformation characteristics and deformation mechanism are discussed. The effect of row piles beside the buildings is also analyzed. The results show that the horizontal deformation of the lining and the land upheaval at the shaft bottom are the important reasons to cause the stratum deformation in the surrounding area. The row piles can interrupt the deformation of foundation and reduce the cumulative settlement and the differential settlement. Finally,the length of the row piles is also discussed. These conclusions are useful for similar project construction.