新蜀河隧道炭质片岩大变形控制技术研究

Research on the Control Technology for Large Deformation of Carbon Schist of Xinshuhe Tunnel

研究目的:长距离的炭质片岩隧道施工中初期支护发生易发生大变形的情况,支护变形、侵限,给现场施工、进度、安全带来了极大的挑战。本文结合新蜀河隧道炭质片岩大变形施工技术,结合以往大变形隧道施工的经验和教训对单线铁路隧道炭质片岩的大变形控制技术及方案进行了总结,为今后类似工程提供参考和借鉴。研究结论:单线铁路隧道采用3台阶临时仰拱法,上台阶设置型钢混凝土仰拱后,应严格地控制台阶、仰拱、二衬的步长,在控制变形方面效果较为明显;大变形隧道应根据监控量测资料预留适度的变形量,对于防止前期初期支护破坏和后期护拱开裂,以及控制工程成本都有着非常重要的意义;隧道通过初期支护壁后注浆,在钢架型号、接头形式位置和纵向连接设置等方面进行改进,并在一定程度上抑制了变形发生;施工中应对长台阶施工或中间拉槽的错误作法严格禁止。

Research purposes： The large deformation easily happens to the primary support during construction of long - distance carbon schist tunnel, and the support deformation and fouling of clearance gauge bring about great challenge to the on -site construction, construction process and construction security. Combined with the control technology for the large deformation of the carbon schist of Xinshuhe Tunnel and the experience in construction of the large deformation tunnel in the past, this paper summarizes the control technology and control scheme for the carbon schist of single - track railway tunnel for providing the reference to the similar works. Research conclusions：The three -step temporary inverted arch method can be adopted to the single -track railway tunnel, with strict control of the step lengths of the step, inverted arch and secondary lining after installation of sectional concrete inverted arch on the top step for getting the perfect control effect. The appropriate deformation quantity should be remained in advance to the large deformation tunnel according to the monitored and measured data. This is essential to prevent of the support＇s damage in early-stage, the protected arch＇s crack in later-stage and the control of construction cost. The tunnel deformation is restrained to some extent after grouting through the back of the primary support wall and improvements of the type of steel frame, the form and location of the joint and installation of the vertical connection. The long step construction or kerve has to be forbidden during construction.