两侧双基坑开挖对密贴地铁车站的影响研究

Influence of Excavation of Double Foundation Pits on Both Sides of the Metro Station

密贴既有地铁车站结构的基坑施工极易造成地铁结构的变形,影响地铁行车安全的同时给财产带来损失。针对以上工程实际问题,以双侧密贴某地铁车站的双基坑工程为依托,采用Midas-GTS大型有限元计算软件,针对钻孔桩围护结构、横撑+预留土台的临时结构安全性及对地铁车站的影响进行分析,开挖步骤以实际施工过程为准。研究表明:施工降水对既有车站的影响主要以水平变形为主,基坑开挖对既有车站的影响主要以竖向变形为主;经过计算检验,该基坑施工后地铁结构竖向变形6.54 mm,水平变形3.88 mm,对既有车站影响较小,且基坑自身结构及临时支撑安全,可作为正式方案进行施工。

The construction of the foundation pit that closely adheres to the existing subway station structure can easily cause deformation of the subway structure,which will affect the safety of subway traffic and cause property losses.In view of the above practical problems of the project,relying on the double foundation pit project closely attached to a subway station on both sides,the Midas-GTS large-scale finite element calculation software is adopted to analyze the safety of temporary bored pile retaining structure,transverse bracing+reserved soil platform and the influence of subway station.The analysis steps should be subject to the actual construction process.The results show that the impact of construction precipitation on the existing station is mainly horizontal deformation,and the impact of foundation pit excavation on the existing station is mainly vertical deformation.According to the calculation,the construction of the foundation pit led to the vertical deformation of the subway structure of 6.54mm and the horizontal deformation of 3.88mm,which had little impact on the existing station.Moreover,the structure and temporary support of the foundation pit were safe and could be constructed as a formal scheme.