赛格水电站导流隧洞出口陡峭地形的围堰设计

The Design of the Diversion Tunnel Outlet Cofferdam Located in a Steep Terrain for the Saige Hydropower Station

赛格水电站经过对土石围堰、混凝土围堰和预留岩塞等方案比选后,摒弃了常规的出口围堰设计方案,而是利用山区性河流洪、枯水位变幅大的特点,提出了洞塞式围堰设计方案,既降低了围堰施工难度,又保证了导流隧洞运行期间的高速水流冲刷下的结构安全,具有施工方便、施工质量易于保证和施工风险小的优点。

The Saige Hydropower Station is located on the Nujiang River in a high mountains and deep valley region of Yunnan Province. In order to adapt the project to the characteristics of steep topography and swift current the throat-type cofferdam scheme is proposed instead of the conventional outlet cofferdam after comparison between earth-rock cofferdam, concrete cofferdam and pre-set rock plug cofferdam considering the large difference in water level of the river between the flood season and the dry season in a mountainous area. The proposed design not only reduces the construction difficulty of the cofferdam, but also guarantees the structure safety of the diversion tunnel under high velocity flow during its operation, which has such advantages as being convenient for construction, easy to ensure quality and low construction risk.