黄土隧道围岩工程性质特殊,只有选择合适的开挖工艺、衬砌支护及监控量测方法才能保证隧道的安全施工。以甘泉隧道为例,利用有限元法对其开挖方法进行了模拟分析。结果表明:双侧壁导坑法对于隧道竖向位移的控制效果较好,CD法次之,上下台阶法较差,因此甘泉隧道Ⅳ级围岩段选用上下台阶法,Ⅴ级围岩段选用CD法,Ⅵ级围岩段选用双侧壁导坑法施工。从隧道的初期支护、二次衬砌、防排水工艺、监控量测、超前地质预报等施工的关键工序及工艺分析了保证黄土隧道施工安全的方法。经甘泉隧道施工验证,所采取的各项工艺合理。
The engineering characteristics of loess tunnel surrounding rock are special, and choosing the proper excavation technology, lining support and monitoring measurement method could ensure the safety of the tunnel construction. Taking Ganquan tunnel as an example, the excavation method was simulated and analyzed by using finite element method. The results showed that double side drift method has a good effect on control of tunnel vertical displacement, CD method has a normal control effect and the control effect of benching tunneling method is poor. The benching tunneling method was used for 1V class surrounding rock section of Ganquan tunnel, CD method was used for V class surrounding rock section and the double side drift method was used for VI class surrounding rock section. Safety construction method for loess tunnel was discussed from the key construction process and technology including tunnel initial support, secondary lining, waterproof and drainage, monitoring measurement and advanced geological prediction, which was proved to be reasonable by the construction of Ganquan tunnel.