海底隧道联络通道机械法施工的结构稳定性分析

Structure Stability Analysis of Subsea Tunnel Link Passage Constructed with Shield Method

青岛地铁8号线海域段盾构隧道联络通道施工具有埋深深、水压高、围岩破碎等特点。使用FLAC 3D软件,对联络通道顶管法施工过程中主隧道及联络通道的力学响应和结构稳定性进行了分析。结果表明:由于联络通道的施工,主隧道的变形由对称转为不对称,变形和应力明显增大;在主隧道与联络通道连接处发生明显的应力集中,尤其是高水压条件下,必须做好加固和防水措施;联络通道的开挖对始发隧道的影响大于接收隧道,施工前可根据主隧道的地质状况确定始发端;洞口破除处的主隧道内架设支撑可有效减小结构变形;洞门破除和支撑拆除两个工况下,主隧道结构变形和受力变化明显,施工中应加强变形监测。

Qingdao Metro Line 8 sea section shield tunnel link passage construction has characteristics of large buried depth, high water pressure and broken surrounding rock. FLAC3D is used to analyze the mechanical response and structure stability of the main tunnel and link passage during pipe jacking method link passage construction. Research results show that: due to the construction of link channel, the deformation of main tunnel changes from symmetrical to asymmetrical, and the deformation and strain increase significantly. Obvious strain concentration occurs at the connection between main tunnel and link passage, especially under the condition of high water pressure, reinforcement and waterproof measures must be taken. Link passage excavation has greater impact on starting tunnel than on receiving tunnel, and the starting end can be determined by main tunnel geological condition before construction. Setting up supports in main tunnel at portal breaking can effectively reduce the structural deformation. Under the two working conditions of portal breaking and support removal, main tunnel structure deformation and stress change are obvious, deformation monitoring should be strengthened during the construction.