| 摘要: |
| 基于长江口北槽深水航道长期定点观测的2006，2008和2011年洪季大潮、2006，2009和2013年枯季大潮水沙数据以及2006和2013年6—8月横沙和北槽中的潮位资料，分析三期工程前后北槽中上段潮汐、潮流及含沙量变化特征。分析结果表明：①中上段浅水分潮性质增强，且M4分潮和M2分潮的振幅变化幅度远大于M2分潮；中段洪、枯季大潮平均潮差均减小；②中段M2分潮流垂线平均长轴洪季大潮增大、枯季减小，长轴向均向北偏转且椭率减少；洪、枯季大潮涨、落潮平均流速均减小，优势流减小；③余流为中段含沙量贡献最主要的驱动力，其次是M4分潮，随后为M2分潮；中段洪、枯季涨落潮平均含沙量均增多，优势沙减小；④中上段潮动力非线性特征加强主要受三期工程中上段缩窄加深工程的影响；南导堤加高工程是中段流速减小的主要原因；洪、枯季优势流、优势沙的差异主要受上游来水来沙的影响；泥沙再悬浮是中段悬沙的主要来源，且洪、枯季含沙量差别主要受上游来水来沙及潮流动力强度控制。 |
| 关键词: 北槽深水航道 含沙量变化 潮汐 潮流 长江口 整治工程 |
| DOI： |
| 分类号:TV148; U617.6 |
| 基金项目:国家自然科学基金资助项目（41340044，41476075）；国家自然科学基金中荷合作专项（51061130544） |
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| Variations in hydrodynamics and sediment concentration in upper-middle section of north passage before and after the third stage of Yangtze estuary deepwater channel regulation works |
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LIU Gao-wei1,2, CHENG He-qin1, YANG Zhong-yong3
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1.State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai;2.Shanghai Estuarine & Coastal Science Research Center, Shanghai;3.College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang
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| Abstract: |
| On the basis of some hydrological data obtained from observation at the upper and middle section of the north passage during the spring tide in the flood and dry seasons from 2006 to 2013, and using the methods of statistics data, harmonic analysis and tidal range’s proportion conversion，analyses of variation characteristics of tidal current and suspended sediment concentration (SSC) before and after construction of the third stage of the Yangtze River estuary deepwater channel regulation works have been made in this paper. The analysis results show that：①the amplitudes of M4 and SM4 tide are strengthened due to the construction of the regulation works in the upper and middle section of the north passage; and the average tidal range decreases in the middle section of the north passage；②after the completion of the regulation works, the deep-average major axis of M2 increases during the flood seasons, while decreases during the dry seasons, and the direction of the major axis in both seasons turns to the north, and the ellipticity decreases. The flood and ebb tide average tidal current velocity decreases no matter whether in the flood or dry seasons, and the preferential flow also decreases; ③in the middle section of the north passage, the most contribution to SSC is residual current, and then is M4, the third one is M2. After the construction of the regulation works, the flow and ebb tide average tidal current velocity decreases, and preferential sand also decreases; ④in the upper and middle section of the north passage, the non-linear characteristics of tide dynamics tend to be strengthened, which is mainly affected by its narrowed deepening works. Heightening the south dike becomes a main factor in reducing the flow velocity along the middle section. The difference between the flood and dry seasons of the preferential flow and preferential sand is mainly affected by the upper incoming flow and the suspended sediment. Sediment resuspension is a major source of the suspended sediment in the middle section of the north passage, and the differences between the flood and dry seasons of the suspended sediment concentration are controlled respectively by the upper incoming flow and the suspended sediment as well as the tidal current dynamic strength. |
| Key words: north passage deepwater channel variation in suspended sediment concentration tide tidal current Yangtze River estuary regulation works |
