三峡水库至坝下游粗细颗粒泥沙输移特性与驱动机制  

Transport Characteristics and Driving Mechanism of Coarse and Fine Grained Sediment from Three Gorges Reservoir to Downstream of Dam

作　　者：王晨阳 杨云平[2] 郑金海[3] 朱玲玲 王建军[2] 杨胜发[1] WANG Chenyang;YANG Yunping;ZHENG Jinhai;ZHU Lingling;WANG Jianjun;YANG Shengfa(School of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Tianjin Research Institute for Water Transport Engineering,Ministry of Transport,Tianjin 300456,China;Yangtze Institute for Conservation and Development,Hohai University,Nanjing 210098,China;Bureau of Hydrology Changjiang Water Resources Commission,Wuhan 430010,China)

机构地区：[1]重庆交通大学河海学院,重庆400074 [2]交通运输部天津水运工程科学研究所,天津300456 [3]长江保护与绿色发展研究院,河海大学,江苏南京210098 [4]长江水利委员会长江水文局,湖北武汉430010

出　　处：《应用基础与工程科学学报》2024年第3期787-800,共14页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(52279066,U2240206);国家重点研发计划项目(2021YFB2600500);江苏省水利科技项目(2020001)。

摘　　要：流域人类活动的增强,深刻影响了河流水文与地貌形态演变过程及发展趋势.三峡大坝作为全球最大的水电工程,其运行对下游水沙通量、泥沙输移、地貌形态等的影响引起了广泛关注.通过1990~2021年三峡水库蓄水对泥沙分选及下游泥沙输移过程影响的研究,加深了人类活动对河流水沙-地貌系统演变的认识.研究结果表明:三峡水库拦蓄了上游流域76.33%的沙量进入大坝下游,细颗粒(d≤0.125mm)和粗颗粒(d>0.125mm)沙量排沙比低于25.0%(24.26%和11.69%);2003年以来三峡大坝下游河段总沙量、细颗粒泥沙沿程得到恢复,其恢复量值低于蓄水前(1990~2002年)平均值;三峡水库运行改变了库区水位及流量过程,库区水位抬升降低了总沙量、粗颗粒及细颗粒泥沙排沙比,汛期(5~10月)入库流量大于30000m3/s天数多的年份细颗粒泥沙排沙比增加、粗颗粒泥沙排沙比保持稳定;三峡水库运行后坝下游宜昌至湖口河段的沙量减少引起河床长距离累积冲刷,细颗粒泥沙沿程得到恢复,因河床逐渐粗化作用引起的粗颗粒泥沙恢复程度呈减弱态势.The enhancement of human activities in the basin has profoundly affected the evolution process and development trend of river hydrology and geomorphology.As the largest hydropower project in the world,the operation of the Three Gorges Dam has caused widespread concern on the downstream water and sediment flux,sediment transport and topography.In this study,the influence of impoundment of the Three Gorges Reservoir on sediment sorting and downstream sediment transport from 1990 to 2021 were studied,which deepen the understanding of human activities on the evolution of river water-sediment-geomorphology system.Results:The Three Gorges Reservoir impounded 76.33%of the sediment in the upstream basin into the downstream of the dam,and the sediment discharge ratio of fine particles(d≤0.125mm)and coarse particles(d>0.125mm)was less than 25.0%(24.26%and 11.69%);The total sediment and fine-grained sediment in the lower reaches of the Three Gorges Dam have been recovered since 2003,and the recovery value is lower than the average value before impoundment(1990~2002);the operation of the Three Gorges Reservoir changes the water level and flow process in the reservoir area,and the rise of water level in the reservoir area reduces the total sediment volume,coarse particle and fine particles sediment discharge ratio,the sediment discharge ratio of fine particles increases and the ratio of coarse particles remains stable in the years with long days of inflow greater than 30000m3/during the flood season(May~October).After the operation of the Three Gorges Reservoir,the sediment volume in the downstream of the dam from Yichang to Hukou is reduced causing long-distance cumulative scouring of the riverbed,and the fine-grained sediment recovered along the way.The recovery of coarse-grained sediment caused by the gradual coarsening effect of the riverbed is in a weakened state.

关 键 词：泥沙分选 输移特征 驱动机制 河床变形 三峡水库 长江中下游 

分 类 号：TV148[水利工程—水力学及河流动力学]