浅埋暗挖法下穿既有盾构隧道的变形特性分析

发布时间：2018-01-21 03:15

本文关键词： 隧道工程既有隧道变形地层变形现场实测　出处：《岩石力学与工程学报》2014年S2期 　论文类型：期刊论文

【摘要】：北京地铁6号线平安里—北海北站区间下穿既有4号线区间隧道工程为北京地区首例暗挖隧道下穿盾构隧道工程。依托该工程,通过12个地表沉降监测断面及既有盾构隧道变形实测数据的统计,分析新建隧道与既有结构的相互影响,对地层及既有结构的变形特性取得以下认识:(1)非下穿段暗挖隧道地表最大沉降值随其埋深增大而减小;双线隧道间距小于2.0D(D为单线隧道宽度)时,地表沉降模式为"单凹槽状",间距大于2.0D时,则为"双凹槽状";下穿段既有结构呈"双凹槽状"变形,地表沉降模式为"单凹槽状"。(2)盾构隧道结构呈柔性变形,纵向柔性更为明显,下穿段既有结构的最大沉降值分别为7.32,6.69 mm,结构变形损失率分别为0.36%,0.45%,结构纵向沉降变形宽度系数为0.41~2.43。(3)下穿段地表最大沉降值为非下穿段的24%~27%,地表沉降槽宽度系数是非下穿段的1.2~2.3倍。既有结构的存在及地层的深孔注浆加固显著减小了暗挖隧道引起的地表沉降值,增大了地表沉降槽宽度。该研究成果可为今后类似工程提供参考。
[Abstract]:The tunnel project of Pinganli-Beihai North Railway Station, Beijing Metro Line 6, is the first tunneling project under shield tunneling in Beijing area, relying on the project. The interaction between the new tunnel and the existing tunnel is analyzed through the statistics of 12 surface subsidence monitoring sections and the actual deformation data of the existing shield tunnel. For the deformation characteristics of strata and existing structures, the following conclusions are obtained: 1) the maximum ground subsidence value decreases with the increase of buried depth. When the distance between two tunnels is less than 2.0 D is the width of single tunnel, the surface subsidence mode is "single groove", and when the spacing is larger than 2.0 D, it is "double groove". The existing structure of the underpass section is "double groove" deformation, and the ground subsidence mode is "single groove". 2) the shield tunnel structure is flexible deformation, and the longitudinal flexibility is more obvious. The maximum settlement of the existing structures in the underpass section is 7.32 mm and 6.69 mm respectively, and the loss rate of the structure deformation is 0.36% and 0.45% respectively. The width coefficient of longitudinal settlement and deformation of the structure is 0.41 ~ 2.43 ~ (3)) the maximum settlement value of the penetrating section is 24 ~ 27% of that of the non-underpass section. The width coefficient of surface subsidence trough is 1.2or 2.3 times of that of non-underpass section. The existence of existing structure and the reinforcement of deep hole grouting can significantly reduce the value of surface subsidence caused by undercut tunnel. The research results can provide reference for similar projects in the future.
【作者单位】：北京交通大学城市地下工程教育部重点实验室;中铁十四局集团有限公司;
【基金】：国家重点基础研究发展计划(973)项目(2010CB732102) 中央高校基本科研业务费专项资金资助项目(2012JBZ013) 国家自然科学基金青年基金项目(51308036)
【分类号】：U455.4;U231.3
【正文快照】： 1引言为缓解日益严重的城市交通压力,地铁建设规模不断扩大,以形成较为完善的地下交通体系。在城市地铁网络的建设中,不同线路间的穿越问题将不可避免。就北京地铁而言,已完成的地铁区间或车站下穿既有线工程有10余个,这些工程项目中包括暗挖结构的相互穿越[1-6]以及盾构隧道

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