强震区极弱千枚岩区域引水隧洞施工技术

Construction technology of water-diversion tunnel in extremely weak phyllite at strong earthquake zone

以高烈度地震区极弱千枚岩区域的涪江古城水电站引水隧洞的施工为例,运用隧道施工理论、系统优化等方法并充分结合现场实际情况,对施工方案进行了分析比较,提出了"短进尺、弱(不)爆破、快封闭、强支护、勤测量"的施工原则,确定了开挖施工工艺流程,进而提出了支护紧跟措施和方法。实践表明,研究出的开挖方法、作业顺序及支护结构与参数可以满足软弱千枚岩隧洞建设需要,能够保证隧洞围岩稳定和结构安全,可为类似工程提供一定参考。

Based on the diversion tunnels construction of extremely weak phyllite in strong earthquake zone at Peijiang Gucheng hydropower station,this paper put forward a construction principle of short footage,weak blasting,quick closing,strong supporting and frequent measuring by using tunnel construction theory and system optimization methods through adequate consideration of the spot situation and reasonable comparison of various construction methods,made out an excavation construction process,and then offered a series of supporting measure.The project practice shows that the excavation methods,working process,supporting structure and parameters can meet the needs of tunnel construction of extremely weak phyllite rock and ensure the surrounding rock stability and the tunnel structure safety,which would provide a reference for some similar projects.