深基坑十字交叉换乘既有地铁车站变形特性分析

摘要

Based on the research data collected at Xiawafang station,which is a cross-transfer sub-way station of Tianjin subway line 5 and line 1,the horizontal displacement of foundation pit sup-port structure,the surface settlement behind the retaining wall,and the deformation of existing station caused by deep foundation pit crossing the existing subway station are analyzed.The re-sults show that the maximum horizontal displacement of support wall is 0.064％ H (in which H is the excavation depth),where is about 0.63H under the ground surface.The maximum ground surface settlement behind the retaining wall is 0.025％ H ,where is about 0.71H away from the wall.The influence zone extends to about 2H from the wall.The ratio between the maximum ground surface settlement and the maximum wall deflection is among 0.38 to 1.04,and its average value is about 0.77.The vertical deformation of the existing station which crosses the foundation pit is mostly uplifted.The horizontal displacement protrudes outside the railway sta-tion.The deformation of the existing station is mainly horizontal.By reinforcing the existing sta-tion with waterproofing sealing and reinforcing its soft soil layer behind the retaining wall,the existing structural deformation can be significantly reduced.%基于新建天津地铁5号线与既有地铁1号线十字换乘车站——下瓦房站的现场实测数据,研究深基坑开挖与既有车站十字相交时,基坑围护结构、墙后地表和既有车站的变形规律.研究结果表明:围护结构最大水平位移约0.064％H(H为基坑开挖深度),位于地表下约0.63H.墙后地表最大沉降约0.025％H,位于墙后约0.71H,沉降槽影响范围约为2H.墙后地表最大沉降与围护结构最大水平位移的比值介于0.38～1.04之间,平均约为0.77.与基坑开挖方向交叉的既有地铁车站竖向上浮,水平方向外凸,以水平变形为主.既有车站周围止水加固和加固墙后软弱土层可显著减小既有结构变形.