大跨度大洞径斜截面隧洞进口开挖施工方法

Construction Method for Inlet Section Excavation of Large-span and Large-diameter Inclined Tunnel

文章介绍岩滩水电站扩建工程尾水隧洞进口开挖施工。隧洞进口一般是正截面进洞,这样洞口容易成洞和安全,但有些受地形及上部结构限制,必须斜截面进洞,岩滩水电站扩建工程尾水出口就是此形式,而且是大跨度大洞径进洞,由于开挖程序支护方式得当,开挖取得了成功。

This paper introduces the excavation of the tailrace tunnel inlet in the Extension Project of Yantan Hy- dropower Station. The tunnel inlet is generally excavated in a normal section, which is more easy and safe for excava- tion, but is required to be excavated in an oblique section when restricted by the topography and the upper structure. The tailrace tunnel outlet of the Project not only requires to be excavated in an oblique section but also has large-span and large-diameter, which obtained a great success due to the proper supporting methods adopted during excavation.