三峡水库蓄水后宜昌至沙市河段冲淤变化分析

Analysis on erosion-deposition variation of Yichang-Shashi reach after impoundment of TGP

三峡水库蓄水运行后,下泄沙量大幅减小,为了解坝下游河道变化情况,运用断面地形法计算分析了宜昌至沙市河段的冲淤变化。从来水来沙变化过程、河床形态、河床组成、比降等方面对冲淤变化的影响因素进行了分析研究。结果表明:河段的冲淤变化是水沙组合、河床组成、河床形态等因素综合作用的结果,其中来沙量的大幅减少是主要因素;不同河段各因素对冲淤变化的影响大小存在差异,即枝城至沙市河段的冲淤强度大于宜昌至枝城河段。

The discharge sediment amount decreases sharply after impoundment of TGP.We analyzed erosion-deposition variation of Yichang to Shashi reach using cross section topography method,and studied the influential factors of erosion-deposition variation in the aspects of inflow water and sediment process,bed configuration,bed composition and gradient ratio.The results show that erosion-deposition variation is influenced by river flow and sediment,bed composition and bed configuration comprehensively,in which the remarkable decrease of inflow sediment is dominate;the influential factors in different reaches affect the erosion-deposition variation in different degrees,and erosion-deposition intensity of Zhicheng to Shashi reach is larger than that of Yichang to Zhicheng reach.