对富水粉细砂地层隧道初期支护拆换处理技术的研究

Study on Initial Support Replacement Treatment Technology for Water-rich Silt and Fine Sand Layer

桃树坪隧道富水粉细砂地层,遇水极易软化,下部泥化现象明显,扰动后基底呈稀湖状,初支钢架接腿和闭合困难,隧道变形大,支护破坏乃至坍塌,局部富水地段掌子面涌水涌砂现象严重,造成初期支护变形侵限。

The water-rich silt and fine sand layer of Taoshuping Tunnel is easy to soften in case of water, and the muddy phenomenon is obvious in the lower part. After the disturbance, the base is in a thin lake shape, so the initial support steel frame is difficult to connect and close, the tunnel deformation is large, the support damage is even in the collapse, and the gushing water and sand of the tunnel face in the water-rich section is severe, which cause the initial support deformation and intrusion.