摘要
依托呼和浩特市新建“S”型地下连接通道近距离上穿既有地铁2号线工程,采用有限元数值模拟和现场监测相结合的方法,对砂袋压重范围、砂袋压重高度以及中隔壁拆除方式进行了对比分析,得出了对既有盾构隧道变形控制的最优方案。研究表明:(1)既有盾构隧道各阶段最大变形位置随新建隧道的掘进而动态变化,施工完毕后最大变形出现在既有盾构隧道远端,这是由于新建隧道开挖至盾构正上方时,该位置受到的施工扰动影响最大,是变形控制的重点区域;(2)采用砂袋压重对既有盾构隧道的变形控制效果较为明显,变形控制效果基本在25%~30%之间,但增加压重范围和压重高度对减小隆起变形幅度影响不大,基本在4%~6%之间,考虑到施工经济性,选用压重范围为49~87榀,压重高度为2.0 m的压重措施方案;(3)采用不同的中隔壁拆除方式对隧道隆起变形有较大影响,为了便于及时形成稳定的受力体系,选用了“隔一拆二”的拆除方式。通过采取合理的砂袋压重措施和中隔壁拆除方式,在上穿施工中有效控制了既有盾构隧道的隆起变形,施工完毕后既有盾构隧道道床变形为2.68 mm,接近道床实测数据2.51 mm,满足规范要求(4.00 mm),可为类似工程提供相关借鉴经验。
Relying on the Hohhot new“S”type underground connecting passage passing through the existing Metro Line 2 project in a short distance,this paper uses the method of finite element numerical simulation and field monitoring to compare and analyze the sand bag weight range,the sand bag weight height and the removal method of the middle wall,and obtains the optimal scheme for the deformation control of the existing shield tunnel.The research shows that:①The maximum deformation position of the existing shield tunnel in each stage changes dynamically with the excavation of the new tunnel,and the maximum deformation occurs at the far end of the existing shield tunnel after the construction is completed,because when the new tunnel is excavated directly above the shield,the position is the key area of deformation control,which is the most affected by the construction disturbance;②The deformation control effect of using sandbag weight on existing shield tunnels is relatively obvious,and the deformation control effect is basically between 25%and 30%,but increasing the weighting range and height has little effect on reducing the uplift deformation amplitude,which is basically between 4%and 6%.Considering the construction economy,the sand bag weighting measure scheme with a weighting range of 49~87 pieces and a weighting height of 2.0 m is selected;③The different demolition methods of the middle diaphragm wall have a great impact on the tunnel uplift deformation.In order to form a stable stress system in time,the demolition method of“one partition and two demolition”is selected.The uplift deformation of the existing shield tunnel was effectively controlled in the upper crossing construction by taking reasonable sand bag weighting measures and the removal of the middle wall.After the construction,the deformation of the existing shield tunnel track bed was 2.68 mm,which was close to the measured data of the track bed of 2.51 mm,meeting the specification requirements(4.00 mm),which can provide relevant reference experience for similar projects.
作者
李宗
秦浩斌
韩瑞林
郭飞
李文博
赵志杰
Li Zong;Qin Haobin;Han Ruilin;Guo Fei;Li Wenbo;Zhao Zhijie(Beijing Municipal Construction Group Co.,Ltd.,Beijing 100089,China)
出处
《市政技术》
2024年第6期89-98,共10页
Journal of Municipal Technology
基金
北京市政建设集团有限责任公司科技创新项目(2021-11)。
