天生桥二级水电站三条引水发电隧洞,采用两种施工方法进行开挖。~#1、~#3支洞施工段为钻爆法开挖;~#2支洞施工段为10.8m全断面掘进机开挖。由于隧洞线处于岩溶发育区,钻爆法施工段在开挖过程遇到许多岩溶段和破碎带,严重地影响了工程的进展。针对不同的岩溶地质情况采取不同的治理方法,具体可归纳为四种方法:管棚混凝土护顶法,锚喷混凝土 Tianshengqiao two hydropower three diversion power tunnel, excavation using two methods of construction. ~ # 1, ~ # 3 branch of the construction section for the drilling and blasting excavation; ~ # 2 branch of the construction section of 10.8m full section boring machine excavation. Due to the tunnel line being in the karst development zone, drilling and blasting construction section encounters many karst sections and broken zones during excavation, seriously affecting the progress of the project. Different karst geological conditions to take different ways of governance, can be summarized into four methods: concrete pipe roof protection law, shotcrete shotcrete