铁路隧道近距离下穿在建公路隧道的施工控制技术

针对回龙湾铁路隧道近距离下穿在建公路隧道施工控制难题,在对两座隧道工程条件特别是空间展布分析的基础上,确定了穿越施工的总体方案与风险控制原则,进而提出了大管棚和T76S自进式管棚超前支护参数、开挖方法与步序、初期支护方法等。现场监测结果表明,选定的下穿隧道施工方案不仅能够较好地控制围岩变形,而且可以保证铁路隧道施工安全,同时也能够保证近距离的上方公路隧道围岩稳定和结构安全。

Construction Control Technology of Railway Tunnel Crossing Underneath the Being-built Highway Tunnel at Short Distance

In light of the construction control problem of Huilongwan railway tunnel crossing underneath the constructing tunnel at a short distance,this paper formulated the overall scheme and risk control principles of the construction after analyzing the engineering conditions,especially spatial distribution of the two tunnels.And then,large pipe shed and T76 S self-propelled pipe shed advance support and its parameters,excavation method and step sequence as well as initial support method were proposed.The field monitoring results show that the deformation of surrounding rock can be well controlled according to the selected construction scheme,which can not only guarantee the construction safety of railway tunnel,but also ensure the stability of surrounding rock and structural safety of the short-distance highway tunnel above.