三峡水库下游河道冲刷粗化研究

Study on scour and armor in the downstream of Three Gorges Reservoir

三峡工程运行10余年以来,水库拦截了上游约75.5%的泥沙,破坏了原天然河道的自然形态与水沙条件的相对平衡,三峡大坝下游河道产生强烈冲刷,致使河床明显粗化。根据三峡水库蓄水后下游河段实测地形及床沙级配资料,分析了河道冲淤变化,并总结了四种床沙粗化计算方法。在此基础上利用接近冲淤平衡的宜枝河段实测资料对四种方法进行了验证计算。研究结果表明,韩其为方法的床沙粗化级配和冲刷深度与实测值吻合较好,较客观地反映了三峡水库下游河道的冲刷粗化过程。

The Three Gorges Reservoir has intercepted about 75.5% sediment from upstream and interrupted the relative balance between water and sediment of the original natural river since the Three Gorges Project operated more than 10 years.The downstream river of the Three Gorges Dam was suffered strong erosion,and resulted coarse riverbed significantly.In this paper,erosion and deposition conditions are analyzed according to the measured terrain and riverbed data.Four methods are summarized for scouring and armoring.Based on the measured data from Yichang to Zhicheng reach which has been close to be relative balance,the four methods are verified.Results of the study show that the coarse sand and scour depth of Han＇s method coincide with the measured data best,objectively reflect the erosion processes in the downstream river of Three Gorges Reservoir.