山口水电站导流洞设计糙率选择与过流能力分析

Roughness Selection and Flowing Capacity Analysis of Design of Diversion Tunnel,Shankou Hydropower Project

山口水电站施工导流采用河床一次断流、混凝土围堰挡水度汛、左岸导流洞过流的导流方式,后期封堵。结合围岩类别,为降低工程造价,设计采用了以边墙喷锚支护、底板现浇混凝土衬砌的结构型式,由于洞室断面较大,隧洞糙率系数的选择成为制约隧洞设计的关键因素。经工程类比与分析,综合采取的糙率系数0.024经过施工考验,过流能力基本满足设计要求,取得了较好的效果。

The construction diversion of Shankou Hydropower Project applies one-time river closure, concrete cofferdam retaining water in flood period and flow diversion through right bank diversion tunnel to be plugged at later stage. The side wall supported with shotcrete and anchor bar and the base slab concrete cast in situ are applied to reduce the project cost. As the cavern section is larger, selection of the roughness coefficient of the diversion tunnel become the key factor of the design of the tunnel Through the engineering analogy and analysis, the roughness eoetticient of 0.024 is applied in consideration of factors. Experienced by construction, the flowing capacity basically satisfies design requirement.