某水电站导流洞出口围堰选型及施工技术

Selection and Construction Technology of Cofferdam at the Outlet of Diversion Tunnel of a Hydropower Station

围堰是水利工程建设中用来围护施工基坑而修建的临时性挡水建筑物,其布置方式对施工期度汛安全、工程进度、成本等均有较大影响。依托某水电站导流洞工程,首先对导流洞出口围堰类型进行优选设计,其次通过对土石围堰、混凝土围堰、叠梁门、混凝土截水墙度汛等多种方案对比,确定了钢结构叠梁门围堰方案,并系统阐述了其施工工艺及施工流程。分析结果表明:导流洞出口围堰利用叠梁门式进行度汛,满足工程安全度汛要求、显著减少围堰工程量、降低工程造价、技术可行性强。

The cofferdam is a temporary water retaining structure built to protect the foundation pit in the construction of hydraulic engineering.Its layout has great influence to the flood safety,project progress and cost.Relying on the diversion tunnel project of a hydropower station,this paper firstly optimized the design of the cofferdam type at the outlet of the diversion tunnel,and then compares various construction schemes such as earth rock cofferdams,concrete cofferdams,stoplogs gate,and concrete cutoff walls.The cofferdam scheme was designed,and the construction technology and construction scheme of the cofferdam were systematically expounded.The analysis results show that the cofferdam at the exit of the diversion tunnel uses the stoplogs gate type to control the flood season,which meets the requirements of the project safety flood control,significantly reduces the amount of cofferdam engineering and the project cost,and has strong technical feasibility.