大跨度双连拱隧道穿越破碎山体力学分析

九华山隧道采用大跨度双连拱穿过两个破碎带.施工方法为三导洞加横通道法,并破除了常规进尺限制.为了确保隧道的施工安全和工期,对施工工序进行了力学分析,并通过施工过程监测对计算数据修正.隧道变形最明显位置在拱顶、拱底;应力比较敏感的位置出现在中墙与左右洞拱脚的交点、拱顶及拱腰,围岩大部分区域是受压的,拱底一小部分出现了局部拉应力.结论指导了施工方案的调整,为同类工程施工提供了重要的借鉴意义.

Mechanical Analysis on Construction Process of Large-span Double-arch Tunnel Through Cracked Rocks

The double - arch was applied in Jiuhua Mountain tunnel and two cracked rocks were drilled through. Method of 3 - heading excavation with across channel was introduced in construction and the general restriction of digging footage was can celled. A mechanical analysis was made and calculated datum was modified by monitoring in construction process to ensure the safety and schedule of tunnel construction. The most distinct distortion of tunnel is at its top and bottom and the more sensible place of stress is in the middle wall and arch foot, vault. A large area of rock is compressed and the tensile region is only in a small part of the vault. This result can serve as a guide to adjusting the construction project as well as important reference for other similar engineering.