| 摘要: |
| 钱塘江河口水沙运动极其复杂，特别是泥沙输移问题历来受到学者们的关注。然而河口涌潮河段的含沙量观测非常困难，目前对含沙量精细化的系统实测分析及其规律研究仍然相对缺乏。为进一步加深对钱塘江河口水沙特性及含沙量输移规律的认识，本文基于钱塘江北岸海宁段在主汛期前需修建的围堰工程及其泥沙冲淤问题为背景，采用2022年4-6月钱塘江盐官段北岸盐官潮位站处连续多日实测含沙量展开分析研究。首先，根据潮差级别（大潮、中潮、小潮）和潮时（涨潮前、涨潮期、平潮期、退潮期）对含沙量数据进行划分和分析。其次，利用从盐官潮位站获取的同时期浊度与实测含沙量进行数据拟合，分别按潮差级别和浊度区间划分得到两组拟合曲线，相关度皆到达0.9及以上。拟合曲线经验证后运用于7月潮位与拟合含沙量的分析对比中。结果表明：大潮时含沙量离散程度最大，中潮次之，小潮最小；小潮的四个潮时含沙量变化不大，中潮和大潮涨潮期时的含沙量均有明显上升，平潮期时含沙量有所下降，经退潮期回归至涨潮前水平；总体而言，含沙量曲线与潮位曲线存在相似的周期性关系，但在退潮期，含沙量会再次出现先升高后降低的过程，这可能是由于退潮流速增加，部分沉降的泥沙再次随水流运动，但随着落憩，退潮流速逐渐变缓，含沙量再次下降。本文研究进一步加深对河口含沙量演变规律的认识，为河口工程的泥沙问题提供借鉴。 |
| 关键词: 钱塘江河口 含沙量 浊度 拟合 潮位 |
| DOI： |
| 分类号:TV TV148.1 |
| 基金项目:华东勘测设计研究院科技项目(KY2022-JG-03-02)；国家自然科学基金青年项目(12002310) |
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| Characteristics of sediment concentration in Yanguan section of Qiantang River Estuary based on measured data before the main flood season |
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HU Zhichao1, ZHU Shenming1, LI Jianxiong2, XU Jiahao3, WANG Shaobin4, XIA Chunchen3
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1.Qiantang River Basin Center of Zhejiang Province;2.POWER CHINA HUADONG Engineering Co Ltd;3.College of Civil Engineering,Zhejiang University of Technology;4.Zhejiang Jiangnanchun Construction Group Co,Ltd
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| Abstract: |
| The water and sediment movement in the Qiantang River estuary is extremely complex, especially the sediment transport has always been concerned by scholars. However, it is very difficult to observe the sediment concentration in the tidal reaches of estuaries. At present, there is still a relative lack of systematic measurement analysis and research on the law of sediment concentration. In order to improve the understanding of water and sediment characteristics in the Qiantang River estuary and based on the background of cofferdam project to be built in Haining section on the north bank of Qiantang River before the main flood season and the problem of sediment erosion and deposition, the measured sediment concentration at Yan Guan tidal gauge station on the north bank of the Yan Guan section of the Qiantang River for several consecutive days from April to June 2022 was analyzed and studied. Firstly, the sediment content data were divided and analyzed according to the tidal range level (spring tide, middle tide, neap tide) and tidal time (before high tide, high tide, flat tide, low tide). Secondly, the turbidity obtained from Yan Guan tidal gauge station in the same period and the measured sediment concentration were used to fit the data. Two groups of fitting curves were obtained according to the level of tidal range and turbidity interval, and the correlation degree was 0.9 or above. The fitted curve was verified and used in the analysis and comparison of the tidal level and the fitted sediment content in July. The results show that the dispersion degree of sediment concentration during spring tide is the largest, followed by middle tide and neap tide. There is little change in sediment concentration during the four neap tides. The sediment concentration increased obviously during middle tide and spring tide, and decreased during flat tide, and returned to the level before high tide during ebb tide. Overall, sediment concentration curve and tidal curve are similar to the cyclical relationship, but at low tide period, sediment concentration will rise again after the first rise to reduce process. This may be due to the increased low tide flow velocity, making part of the settlement of sediment motion again with flow. After that, the ebb tide velocity gradually becomes slow, the sediment content decreases again. This study will improve the understanding of the evolution law of the sediment concentration in the estuary, which provides a reference for the sediment problems in the estuary engineering. |
| Key words: Qiantang estuary sediment concentration turbidity fitting tide level |
