再分析卡里巴拱坝下游河床冲刷严重的原因

Re-considering reason of serious scour produced in Kariba Dam

卡里巴 (Kariba)拱坝下游河床冲深达 5 7～ 80m ,是世界上河床冲刷最为严重的拱坝 ,有着其地质、泄水布置等方面的原因。其中主要原因是泄水中孔出口佛劳德数较低 ,6股水舌入水后能量聚集 ,同时河床又未采取保护措施。总结其经验可避免类似冲刷在我国出现 ,对小湾、溪落渡等高拱坝护坡不护底水垫塘的论证有着重要意义 。

Scour depth in Kariba Dam reaches 57 [similar to] 80 m. This is the most serious one in the world. There are many reasons in the aspects of the geology and the arrangement of the outlets. The primary causes generating scour are that the Froude numbers of releasing outlets are relatively low, the energy of 6 nappes entering downstream water body is highly concentrated, meanwhile, there was no any bed protection measure. Summing-up the experience can avoid the similar serious scours in China. This is significant for demonstrating the feasibility of water cushion pool without bottom lining but with protecting both bank slopes in Xiaowan and Xiluodu Projects. And it can be also used as a reference for other water projects.