近期长江口南槽河道滩槽冲刷及驱动因素分析  

Analysis of the Bottom Evolution and the Driven Mechanisms in the South Passage of Yangtze Estuary Over the Recent Years

作　　者：郭兴杰[1,2] 王寒梅 史玉金[1] 秦昌杰[1] 裘诚[3] GUO Xingjie;WANG Hanmei;SHI Yujin;QIN Changjie;QIU Cheng(Shanghai Institute of Geological Survey,Shanghai 200072 China;State Key Laboratory of Marine Geology,Tongji liniversity,Sliiinghai 200092 China;Shanghai Marine Environmental Monitoring and Forecasting Cente,Shanghai 200062 China)

机构地区：[1]上海市地质调查研究院,上海200072 [2]同济大学海洋地质国家重点实验室,上海200092 [3]上海市海洋环境监测预报中心,上海200062

出　　处：《应用基础与工程科学学报》2021年第4期785-796,共12页Journal of Basic Science and Engineering

基　　金：上海市财政项目长江河口及近岸海域综合地质调查资助。

摘　　要：河口地形演化关系到航运通畅、生态保护以及近岸工程的安全性,也是地貌学和工程学关注的热点.2011~2017年间利用单波束测深系统对长江口南槽、南汇边滩北岸和九段沙南岸进行高精度监测,并结合水沙数据和周围工程的建设情况分析其冲淤格局和驱动因素.结果表明:(1)南汇东滩围垦后沿岸基本呈局部冲刷态势,南槽河道、江亚北槽冲刷明显,南汇南滩和江亚南沙淤积;(2)长江上游输沙对-5m深河槽地形演化有较为明显的影响,工程建设对岸滩0m和-2m深岸滩影响较为明显;(3)三峡大坝、深水航道整治工程、南槽航道疏浚、南汇东滩围垦工程等都是导致冲刷的原因,其中南汇东滩围垦对涨潮流的挤压作用是导致九段沙南岸冲刷的主要原因;(4)人类活动可对南槽河道滩槽的演化格局有较为重要的影响,滩涂岸线的固定制约了河槽的摆动,但也加剧了局部岸坡的冲刷,未来应注意九段沙南岸和江亚南沙湿地的监测与保护.The evolution of estuarine topography is closely related to the costal engineerings, e.g.,navigation, ecological and et al, thus is one of the hot topics in the studies of estuarine geomorphology as well as engineering.The patterns of riverbed evolution and the driven mechanisms were analyzed based on the high resolution monitor of topography in the South Channel of the Yangtze Estuary, the North Bank of Nanhui Beach, and the South Bank of Jiuduansha Shoal by using single-beam sounding system during 2011 to 2017.In addition, the observation of hydrodynamics and sediment dynamics as well as the man-made projects in the surrounding area were applied to our analysis.The results are summarized into four aspects.(1)A scouring trend is observed along the coastal of Eastern Nanhui Beach, especially in the South Passage and Jiangya North Passage, after the reclamation of Eastrtn Nanhui Beach, while the siltation in the Southern Nanhui Beach and the Jiangyanan Shoal is examined.(2)The evolution of-5 m isopach is closely related to the variation of upstream sediment discharge in Yangtze River, while that of 0 m and-2 m isopach is closely related to the surrounding manmade projects.(3)The driven factors of scouring trend in Yangtze estuary includes: Three Gorges Dam, Deep Water Channel, navigation dredging in South Channel, reclamation in Eastern Nanhui Beach, and so on, in which, the erosion of Southern Jiuduansha shoal could be ascribed to the squeezing effect on flood current due to the reclamation in Eastern Nanhui Beach.(4)The evolution of shoal-channel pattern in South Passage is sensitive to anthropogenic activity.The embankment project along the shore line holds on the swing of river channel, but aggravates the erosion of local banks.In the future, more attention should be paid to the monitoring and protection of the Southern Bank of Jiuduansha shoal and the Jiangyanan shoal.

关 键 词：南槽 南汇东滩 九段沙 围垦工程 冲刷 淤积 人类活动 

分 类 号：TV185[水利工程]