临近地铁站深基坑工程安全评估分析

天津松江东南角二期基坑工程,周围环境复杂,紧邻天津地铁东南角站,因此在其施工作业前应对周边建筑造成的潜在位移影响进行评估,并进行监测。以此为工程背景,结合数值计算分析等手段,预测基坑的开挖对车站的影响程度及可能带来的危害,从而对基坑工程的施工方案、设计、加固及东南角站的运营管理提出指导性的意见,对危险部位事先采取防范措施。结果表明基坑大面积开挖产生的卸荷效应显著,导致坑外土体产生趋向坑内移动的趋势,在土体变形传递效应的影响下地铁车站以及隧道产生一定的沉降和水平位移,基坑降水的影响并不十分显著,一期大基坑开挖对隧道变形影响显著,尤其是对隧道水平位移。建议在大基坑和隧道之间预设注浆纠偏措施并加强变形监测,保证隧道安全。

Analysis and Safety Assessment of a Deep Foundation Pit Adjacent to the Subway Station

Phase Ⅱ foundation pit of Tianjin Songjiang is adjacent to the southeast corner of subway station with the com-plicated surroundings ,so its potential displacement impact of the surrounding buildings should be evaluated before the construction work .This paper combined forecast the influence degree of the foundation pit excavation on the station and possible damage through the numerical calculation and analysis to guide the construction scheme ,the design and the rein-forcement and the southeastern corner station operation management .Results show that large area excavation unloading ef-fect is significant which resulting in soil pit outside the pit mobile trend ,however ,the precipitation of foundation pit is not significant in displacements ,the influence of the phase I has obvious effects on the horizontal displacement of the tun-nel .Finally suggestions such as deformation monitoring should be taken to ensure the safety of the tunnel .