龙滩碾压混凝土围堰设计与施工

龙滩RCC围堰工程量大、工期紧、施工强度高。其设计除考虑了正常挡水工况外,还考虑了超标准洪水的过水保护。围堰采用两岸堰肩不过水、中间堰段预留缺口形式,下游围堰缺口设置自溃子堰、堰身段设置缓闭止回退水阀门,上游围堰堰后坡面仅设置6.00 m宽消能平台,遇超标准洪水时基坑过水前进行预充水。围堰建成后两年来运行情况良好。

Design and Construction of RCC Cofferdam for Longtan Hydropower Station

The RCC cofferdam for Longtan hydro project is big in project quantities,short in construction period and high in construction intensity.Its design not only should consider the normal water retaining condition but also should consider the overflow protection of super-standard flood.The cofferdam adopts non-overflow on two abutment of cofferdam and pre-left notch on middle section of cofferdam.Its downstream cofferdam notch sets a self-destroy weir with a slow-close non-return water gate.The downstream slope of its upstream cofferdam sets a 6.0m energy dissipation platform.When super-standard flood occurs,its foundation pit will make pre-fill water before water overflows it.Two-year operation after its completion showed that its operation is good.