黄土隧道软弱围岩微台阶快速施工技术研究

Research on Rapid Construction Technique of Micro-step in Weak Surrounding Rock of Loess Tunnel

蒙西至华中铁路穿越陕北黄土高原,存在大量浅埋、偏压和滑坡等复杂地质条件。采用多分部方法施工时,施工组织局限性大,初期支护不能及时封闭成环,特别是富水黄土段落,围岩软化后易造成坍塌,存在安全隐患。黄土隧道软弱围岩微台阶快速施工技术践行快挖、快支、快封闭的原则,采取加强超前支护和合理设置台阶参数的措施,优化施工工序,做到初期支护快封闭、早成环,解决了黄土软岩隧道施工工效低的问题,确保了隧道施工质量、进度和安全。该技术具有安全可靠、机械化程度高、经济效益显著等特点,可广泛应用于水利、公路、铁路工程施工领域。

The Mengxi-Huazhong Railway crosses the Loess Plateau in northern Shaanxi,and there are a lot of complex geological conditions such as shallow burial,bias and landslides.When the multi-division method is used for construction,the construction organization is limited,and the initial support fails to close the loop in time,especially the water-rich loess section is prone to collapse after the surrounding rock softens,and there are hidden safety risks.The rapid construction technology of micro-step in the weak surrounding rock of the loess tunnel implements the principles of fast excavation,fast support,and fast closure,adopts the measures to strengthen advance support and reasonable setting of step parameters,optimizes the construction process,and achieves quick closure and early closed loop of the initial support.The loop formation solves the problem of low construction efficiency of the soft rock tunnel in the loess and ensures the quality,progress and safety of the tunnel construction.The technology has the characteristics of safety,reliability,high degree of mechanization,and significant economic benefits.It can be widely used in the construction of water conservancy,highway,and railway projects.