软岩大变形隧道二台阶带仰拱开挖法施工技术

Construction Techniques of Two Steps with Inverted Arch for the Soft Rock Large Deformation Tunnel

软岩大变形时围岩强度低、受台阶开挖扰动影响大、变形稳定所需时间长,需要快速使初支闭环,快速减少变形速率,快速使围岩稳定。成兰铁路杨家坪隧道洞身地质为千枚岩软岩,中薄层结构,陡倾,与隧道小角度相交,易发生大变形。文章针对杨家坪隧道特殊软岩大变形特点,重点介绍了二台阶带仰拱开挖法在大变形控制和防治的施工技术及优点,为软岩大变形防治提供了新的处治方法。

In the large deformation of soft rock, the strength of rock is low, the disturbance of step excavation is great, the deformation is long.It needs to quickly make the primary support closed-loop, quickly reduce the deformation rate, and quickly stabilize the rock.ChengLan railway Yangjiaping Tunnel geological is phyllite rock, middle-thin layered structure, steep, and small angle intersection with the tunnel, easy to occur large deformation.According to the large deformation characteristics of the special soft rock of Yangjiaping Tunnel, this paper introduced the construction techniques and advantages of Two Steps with Inverted arch in large deformation control and prevention, and provided a new treatment method for the prevention and treatment of the large deformation tunnel.