小净距平行叠落矿山法隧道设计与施工技术研究

查阅近接隧道施工影响区及相应工程对策的研究成果,调研国内部分叠落矿山法隧道工程的相关设计、施工经验。针对用矿山法施工的北京地铁19号线金融街站—平安里站区间与3号线阜成门站—平安里站区间上下叠落4孔隧道工程,分析后行下洞隧道开挖对既有上洞隧道结构及周边环境的影响,提出结合工程实际情况的设计、施工技术措施。利用MIDAS-GTS进行施工过程数值模拟,得到各施工阶段对既有区间结构、地表沉降的影响及其变化过程。研究结果表明:在北京地区采用上下叠落4孔隧道进行设计施工是可行的,通过采取先行隧道超前注浆、加强隧道初期支护及二衬刚度、加固夹层岩体等措施,能满足隧道设计要求。可为类似工程的设计和施工提供一些指导。

Design and Construction Technology for Small ClearanceOverlapping Tunnels Built by Mining Method

This article reviews the research results of the adjacent tunnel affected area and corresponding countermeasures. It also investigates the relevant design and construction experience of a domestic overlapping tunnel. Considering the overlapped four-hole tunnel of Beijing Metro Line 19, Financial Street Station to Pinganli Station, and Line 3, Fuchengmen Station to Pinganli Station, the influence of the excavation of the lower tunnel on the deformation of the existing upper tunnel was studied. Several technical design and construction measures have been proposed. The construction process was analyzed with MIDAS-GTS, and the influence of the construction stage on the existing structure, surface settlement, and change process were discussed. The research indicates that it is feasible to design and construct overlapped four-hole tunnels in Beijing by taking such measures as advanced grouting, strengthening the stiffness of the initial support and permanent support, and strengthening the interlayer soil, which can meet the tunnel design requirements. The study can further provide guidelines for the design and construction of similar projects.