单洞双线铁路隧道仰拱施工质量控制技术研究

为有效解决和控制仰拱厚度不够、强度不足、施工缝翻浆冒泥及上拱等施工质量问题，保障隧道工程建设和运营安全，依托渝昆高铁昭通隧道工程，采用隧道扫描系统检测仰拱开挖断面，确保仰拱厚度满足设计要求；采用液压自行式整体仰拱栈桥，优化仰拱弧形模板，实现分段分层浇筑和振捣工艺，提高混凝土施工质量；采用分离式仰拱端头钢模板，预铺仰拱端头弧形带并安装橡胶背贴和中埋止水带，提高了施工缝质量，减少了施工缝翻浆冒泥现象；设置隧底纵向排水管及逆向导水管等优化隧底排水设计措施，解决了水害造成的仰拱上拱问题；制定并落实隧道仰拱施工质量管理措施。通过在渝昆高铁昭通隧道施工中采取以上措施，实现了仰拱零欠厚，仰拱混凝土强度满足设计要求，施工缝质量零缺陷。

Construction Quality Control Technology of Inverted Arch of Single tube Double track Railway Tunnel

In order to effectively solve the construction quality problems such as insufficient thickness and strength of inverted arch, grouting and mud gushing from construction joints and upward arch, and ensure the safety of tunnel construction and operation, the tunnel scanning system is used to detect the excavation section of inverted arch of Zhaotong Tunnel project of Chongqing Kunming High speed Railway, so as to ensure that the thickness of inverted arch meets the design requirements. And then the hydraulic self propelled integral inverted arch trestle is adopted to optimize the inverted arch arc template, realize sectioned and layered grouting and vibration, and improve the quality of concrete construction. The separate type steel formwork at the inverted arch end is used, the arc shaped belt at the inverted arch end is pre laid, and rubber back paste and medium steel plate embedded water stop belt are installed, which improves the quality of construction joint and reduces the occurrence of mud gushing in construction joint. The longitudinal drainage pipe and reverse water diversion pipe at the tunnel bottom are set to optimize the drainage design measures, which help to solve the problem of upward arch caused by water damage. Finally, the construction quality management measures for tunnel inverted arch are formulated and implemented. By adopting the above mentioned measures in the construction of Zhaotong Tunnel of Chongqing Kunming High speed Railway, the thickness and the concrete strength of the inverted arch and the construction joint quality meet relevant design requirements.