长凼子隧道出口主洞溶洞处理施工技术

Treatment Techniques for the Main Karst Cave at the Outlet of the Changdangzi Tunnel

长凼子隧道出口端掘进过程中掌子面拱部右侧岩壁上遇到了一个大溶洞,根据溶洞的具体情况,制定了采取先清除危石淤泥,尔后用锚喷网支护加固洞壁,再用砼封堵溶洞下部,疏导、排放岩溶水等综合处理方案,取得了成功。可为同类工程借鉴。

The big karst cave found in the left rock wall of the arch section of the work face at the outlet of the Changdangzi Tunnel in the process of excavation is introduced in the paper. With the specific geological conditions of the karst cave taken into account, worked out are a few comprehensive treatment schemes, which prove successful in practice and are described as follows：first removing dangerous rocks and mud, then solidifying the tunnel wall with the anchoring-and-shotcreting-net supports, stopping and sealing up the lower part of the karst cave, and dredging and draining karst water. The project may serve as a useful reference for other similar ones.