隧道下穿暗河施工技术

研究目的：通过对五爪观暗河的处理，总结出一套经济合理、安全可行的隧道下穿暗河的施工方法，确保隧道施工及运营安全，为类似工程积累经验。研究方法：工程类比和现场试验。研究结果：通过采用上游注浆截流堵水使地下暗流走行于隧道之上、岩堆体内深孔注浆堵水加固相结合治理暗河方案，以及洞外堆积体内动水注浆、洞内小导管注浆、台阶法开挖、强支护，隧底钢管桩注浆加固等一系列工程措施，五爪观隧道成功下穿暗河。研究结论：在岩堆体敞开式边界条件及高富流动水状态下，根据暗河工程地质和水文地质条件，采用“分区分序、多泵联合、多浆组合、快凝早强”等关键技术，可有效解决注浆截流、抬高地下水位、隧道下穿暗河堆积体开挖支护的施工难题。

Construction Technology for Tunnel Unerpassed Underground River

Research purposes: By making treatment of underground river at Wuzhaoguan,a set of economic,safe and feasible construction methods of tunnel excavated below through underground river were summarized so as to guarantee the safety of construction and operation,which provided experience for similar construction.Research methods:The engineering comparison and site experience were made.Research results:Wuzhaoguan Tunnel were passed below through underground river successfully,by adopting the scheme of grouting interception and ponding to make undercurrent flow above the tunnel and by deep-hole grouting to strengthen the accumulation body.A serious of engineering measures were used,such as grouting at moving water state in the accumulation body,small pipe-proof protection,powerful support,short bench cut method,tunnel foundation root by steel-pipe pile grouting,etc.Research conclusions:According to underground river engineering geological and hydrogeological conditions,this paper adopted the key technologies of "partition and sequence,multi-joint pump,more slurry mix,rapid solidification and early strength",effectively resolve the problems of the grouting closure and raising groundwater levels and tunnel excavation beneath the underground river accumulation in the rock-open-boundary conditions and high water flows rich state.