溪洛渡水电站左岸特大断面导流洞开挖技术

溪落渡水电站左岸导流洞洞身为城门洞型的特大型断面,其断面尺寸、开挖强度、施工难度都很少见。施工中精心组织,精心管理,广泛应用了各种新材料、新工艺、新技术、新设备。顶拱采用先中导洞,跟进两侧扩挖与支护；中层采用两侧预裂、中间垂直深孔梯段爆破；下层采用水平光面爆破。安全、优质、高效地完成了导流洞的开挖,对今后类似工程的施工有一定的借鉴作用。

Excavation of the diversion tunnel with super large cross -section on the left bank of Xiluodu hydropower plant

The diversion tunnel on the left bank of Xiluodu hydro power plant is of a super large horse-shoe cross -section. Great challenges were met with during its excavation.Elaborate design and construction were followed in the process.New materials,technologies,techniques and equipments were adopted.Upper section of the tunnel was excavated with a central heading,enlarged on the two sides with support installed.Middle layer was excavated by pre-split blasting on two sides and with vertical deep bore holes and stepped blasting for the middle part,Bot- tom layer was excavated by horizontal smooth blasting.The excavation of the diversion tunnel was successfully ac- complished.The practice can be referred to by similar projects.