长江口泥沙运动形式分类及对深水航道淤积影响  

Classification of sediment transport forms in the Yangtze Estuary and its influence on sedimentation in the deepwater navigational channel

作　　者：程海峰 刘杰 韩露 王珍珍 张国庆 叶婷婷 CHENG Haifeng;LIU Jie;HAN Lu;WANG Zhenzhen;ZHANG Guoqing;YE Tingting(Key Laboratory of Estuarine and Coastal Project,Ministry of Transport,Shanghai Estuarine and Coastal Science Research Center,Shanghai 201201,China;State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]上海河口海岸科学研究中心河口海岸交通行业重点实验室,上海201201 [2]河海大学水文水资源与水利工程科学国家重点实验室,江苏南京210098

出　　处：《水科学进展》2022年第5期754-765,共12页Advances in Water Science

基　　金：国家自然科学基金资助项目(U2040204);上海市科技创新行动计划项目(21DZ1201002)。

摘　　要：潮汐河口泥沙运动复杂多变,科学划分泥沙运动形式并评估其对航道淤积的影响,是厘清航道淤积泥沙来源、制定有效减淤措施的关键。基于长江口深水航道所处南港—北槽河段2015年和2018年洪季、枯季表层沉积物和近底悬沙的现场采样数据,分析提出潮汐条件下推移质、悬移质和时推时悬泥沙3类泥沙运动形式的粒径划分方法,量化3类泥沙对深水航道淤积的贡献比例。结果表明:近底悬沙级配曲线上拐点粒径对泥沙由推移质向悬移质转化具有较好的指示意义;长江口南港—北槽悬沙、底沙交换显著,深水航道淤积物中除仅做推移质或悬移质运动的泥沙外,还包括大量的时推时悬泥沙,其在航道淤积泥沙中的占比最高,约达50%~60%;南港段航道洪季、枯季推移质淤积占比分别为36%和26%,高于悬移质的6%和13%;北槽段航道悬移质落淤泥沙占比为44%~48%,明显较推移质3%~6%的占比高。3类泥沙运动形式粒径划分方法为深化潮汐河口泥沙运动规律认识、判别航道淤积泥沙来源提供了新途径。Sediment transport in tidal estuaries is complex and changeable.How to scientifically classify the forms of sediment transport and evaluate its impact on channel sedimentation is the key to clarify the source of sediments deposited in the channel and formulate channel siltation reduction measures.In this paper,a new method identifying three forms of sediment transport,that is the bed load(BL),the suspended load(SL)and the bed-suspended conversion load(BSCL),was proposed based on analyzing the grain size of surficial bed sediment(SBS)and near bottom suspended sediment(NBSS).The sediment samples were collected along the Deepwater Navigational Channel(DNC)in the Yangtze Estuary(YE)during the flood and dry seasons of 2015 and 2018,and the contributions of three forms of sediment transport to the channel sedimentation was quantified.The results show that the upper turning point of grain size cumulative frequency curve is able to well represent the sediment transport form transition from BL to SL.There exists a significant sediment exchange between SBS and NBSS at the South Channel(SC)as well as the North Passage(NP)of YE.The sediment transport in DNC are not only in forms of BL and SL,but also in BSCL,which accounts for the proportion of 50%to 60%of the channel sedimentation.The contribution of BL to the channel deposition at SC segment of DNC in flood and dry season are 36%and 26%respectively,which is higher than that of SL occupying 6%and 13%.In contrast,the contribution of SL to the channel deposition at NP segment of DNC ranges from 44%to 48%,which is much higher than that of BL only accounting for 3%to 6%.The proposed method based on the grain size analysis provides a new sight on understanding the characteristics of sediment movement in tidal estuary and identifying the source of sediments deposited in the channel.

关 键 词：推移质 悬移质 时推时悬泥沙 航道淤积 长江口 

分 类 号：TV142[水利工程—水力学及河流动力学]