长江武汉河段平滩及枯水河槽形态近期调整的机理研究  

Study on the mechanism of recent channel adjustment during bankfull and low-water in the Wuhan reach of the Yangtze River

作　　者：姚记卓 夏军强[1] 周美蓉[1] 邓珊珊[1] YAO Ji-zhuo;XIA Jun-qiang;ZHOU Mei-rong;DENG Shan-shan(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan,430072,China)

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072

出　　处：《泥沙研究》2021年第1期25-33,共9页Journal of Sediment Research

基　　金：国家重点研发计划课题(2016YFC0402305);国家自然科学基金项目(51725902,51579186)。

摘　　要：依据实测水沙及地形资料,分析了长江武汉河段近期平滩及枯水河槽形态的调整特点,确定了其与来水来沙及河床边界条件等因素之间的相关关系。三峡工程运用后,进入武汉河段的沙量大幅度减小(汉口站年均沙量仅为1.03亿t/a),河床冲刷较为显著,2001-2016年该河段平滩河槽累计冲刷量近1亿m^(3)。平滩及枯水河槽形态参数计算表明:近期河段平滩水深增加约1.8 m,但平滩河宽基本不变,面积相应增加约8%,故断面形态整体趋于窄深。由于枯水位下降与枯水河槽冲刷幅度基本一致,因此枯水河槽形态调整不明显,但枯水河槽宽深比在近些年略有减小。分析了河段尺度的平滩特征参数与各影响因素之间的关系,发现平滩水深及过水面积与前期水沙条件之间相关系数可达0.95,表明本文提出的经验关系能较好地反映水沙条件变化对平滩河槽形态调整的影响。To study the characteristics and influence factors of recent channel adjustments in the Wuhan reach of the Yangtze River,bankfull and low-water channel dimensions at both section-scale and reach-scale were studied annually from 2003 to 2016. Empirical relationships were proposed between bankfull channel dimensions and influencing factors. Results show that the sediment load entering the Wuhan reach was significantly reduced after the TGP operation,with a annual average sediment discharge of 103 million t/a at the Hankou Hydrometric Station. A remarkable process of channel degradation occurred in the reach,with a cumulative volume of bed scour about 1. 0×10^(8) m^(3) under the bankfull level. Calculations of bankfull and low-water channel dimensions indicate that the reach-scale bankfull depth increased by about 1. 8 m,and the bankfull width remained unchanged during the period 2003-2016,with a relative bankfull area increase by 8%,which caused a narrow and deep cross-sectional geometry. The reduction degree of low water levels in the Wuhan reach accorded with the scour magnitude in the low-water channel geometry,with an insignificant variation in low-water channel geometry. The width-depth ratio under the low water level reduced gradually in recent years,which generally improved the conditions of navigation channel. Various factors influencing the adjustments in the bankfull channel geometry of the Wuhan reach were analyzed to found that the reach-scale bankfull depth and area correlated with the previous five-year average fluvial scour intensity during flood seasons,with a correlative coefficient of 0. 95.

关 键 词：河床调整 平滩河槽 枯水河槽 水沙条件 武汉河段 三峡工程 

分 类 号：TV147.5[水利工程—水力学及河流动力学]