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。 Since the Three Gorges Project was operated for more than 10 years, the reservoir has intercepted about 75.5% of the sediment in the upper reaches, undermined the relative balance between the natural form of the original natural channel and the conditions of water and sediment, resulting in strong erosion of the river channel downstream of the Three Gorges Dam, resulting in obvious coarsening of the riverbed. According to the measured terrain and sediment distribution data of the downstream reaches after the impounding of the Three Gorges Reservoir, the change of scouring and silting in the river channel is analyzed, and four calculation methods of sediment coarsening are summarized. On this basis, the four methods are validated and calculated by using the measured data of Yichang reach close to the scouring and silting balance. The results show that the coarse sand grading and scouring depth of Hanqi method are in good agreement with the measured values, which objectively reflect the scouring and roughening process of the lower reaches of the Three Gorges Reservoir.