矿山法施工双线铁路隧道二次衬砌拱部预制拼装结构的设计与工程应用

Design and Engineering Application of Prefabricated Structure for Secondary Lining Arch of Double-Track Railway Tunnels Constructed by the Mining Method

  • 摘要: 矿山法隧道采用模筑现浇混凝土衬砌时无法完全消除隧道拱部存在的混凝土衬砌厚度不够、强度不足、开裂掉块和背后脱空等常见质量缺陷,对铁路隧道的长期安全运营构成威胁。以重庆铁路枢纽东环线胡家沟隧道为依托工程,提出了复合式衬砌中拱部采用预制块和边墙模筑衬砌相组合的拼装二次衬砌,分析了拱部预制衬砌的分块方式和接头构造,总结了该预制拼装衬砌结构的施工工艺和经济性,并根据现场监测结果分析了衬砌结构的 安全性和耐久性。结果表明:胡家沟隧道拱部预制衬砌试验段所设计的初期支护和装配式二次衬砌结构参数是可行的,且衬砌具有一定的安全储备;拱部预制衬砌和模筑边墙的接头形式宜设计为圆弧形;拱部预制拼装二次衬砌方案的总造价比模筑二次衬砌的总造价增加了314.71万元,综合造价增加了2.86万元/m。

     

    Abstract: Tunnel construction through the mining method with cast-in-place concrete lining often fails to complete? ly eliminate common quality defects, such as insufficient thickness of concrete lining, insufficient strength, cracking and spalling, and void behind in tunnel arch, which poses threats to the long-term safe operation of railway tunnels.This paper relies on the Hujiagou Tunnel Project of the East Ring Line of Chongqing Railway Hub and proposes to use assembled secondary lining for the arch of the composite lining by combining prefabricated blocks and sidewall molded lining. This paper analyzes the blocking method and joint structure of the prefabricated lining in the arch,summarizes the construction process and economy of the prefabricated lining structure, and analyzes the safety and durability of the lining structure according to field monitoring results. The results show that the structural parameters of the initial support and assembled secondary lining designed for the prefabricated lining test section of the arch of the Hujiagou Tunnel are feasible, and the lining allows for sufficient safety; The form of joints for the prefab? ricated lining of the arch and the cast-in-place sidewall should be designed in the form of a circular arc; The total cost of the scheme of secondary lining with prefabricated arch increases by RMB 3,147,100 compared with the total cost of the cast-in-place secondary lining, and the comprehensive cost increases by RMB 28,600/m.

     

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