| 长江荆江河段滩槽演变与航道水深资源提升关系 |
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| 引用本文： | 杨云平,李明,刘万利,朱玉德,杨丽洁,余文钧.长江荆江河段滩槽演变与航道水深资源提升关系[J].水科学进展,2022,33(2):240-252. |
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| 作者姓名： | 杨云平 李明 刘万利 朱玉德 杨丽洁 余文钧 |
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| 作者单位： | 1.交通运输部天津水运工程科学研究所, 天津 300456 |
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| 基金项目： | 国家重点研发计划资助项目2018YFB1600400国家重点研发计划资助项目2021YFB2600500 |
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| 摘 要： | 长江是中国的"黄金水道", 通过系统性航道整治和疏浚维护, 长江荆江河段航道水深已由2002年的2.9 m提升至2020年的3.5~3.8 m, 但仍低于上游三峡大坝库区(4.5 m)及下游河段(4.5~6.0 m), 航道水深与上下游不衔接且制约长江航道综合效益发挥。为了适应上下游航道水深, 需提升荆江河段航道尺度, 亟需明确航道水深资源、碍航特征与河道演变等关系。以长江荆江河段为对象, 分析1960—2020年水沙及地形等资料, 开展长江中游荆江河段滩槽演变与航道水深资源提升关系研究。研究表明: 三峡工程运行后荆江河段以枯水河槽冲刷为主, 冲刷量占全部冲刷量的90.97%, 江心洲和边滩面积减少18.3%, 其中江心洲、边滩面积减幅分别为9.4%和24.9%;在河床冲刷与航道整治工程实施条件下, 以4.5 m×200 m(水深×宽度)进行航道尺度核查, 荆江河段碍航总长度占全河段5.3%;4.5 m水深碍航特征包括砂卵石河段枯水位下降幅度高于河槽下切深度引起航道水深不足, 沙质河床内弯曲河段"凸岸侧边滩冲刷、凹岸侧深槽淤积"引起滩槽形态及航道边界不稳定, 以及分汊河段内洲滩萎缩与汊道间不均衡冲刷引起枯水航路不稳定及水深不足。
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| 关 键 词： | 滩槽演变 汊道分流关系 航道水深资源 荆江河段 长江中游河段 |
| 收稿时间： | 2021-10-20 |
Study on the relationship between beach trough evolution and navigation obstruction characteristics in Jingjiang reach of the Yangtze River |
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| Affiliation: | 1.Tianjin Research Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China2.Changjiang Waterway Survey Design and Research Institute (Wuhan), Wuhan 430040, China3.National Engineering Research Center for Inland Waterway Regulation, Wuhan 430040, China4.State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China |
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| Abstract: | The Yangtze River is China′s "golden waterway". Through systematic waterway improvement projects and dredging maintenance, the channel depth of the Jingjiang reach downstream of the Three Gorges Dam has increased from 2.9 m in 2002 to 3.5—3.8 m in 2020. However, the water depth is still lower than that of the upstream Three Gorges Dam reservoir area (4.5 m) and the downstream reach (4.5—6.0 m). The water depth of the Jingjiang reach does not connect with the upstream and the downstream, which restricts the comprehensive benefit of the channel of the Yangtze River. In order to adapt to the water depth of upstream and downstream, it is necessary to improve the channel scale of the Jingjiang reach, and it is urgent to clarify the relationship between channel water depth resources, navigation obstruction characteristics and river evolution. Based on the data of discharge, sediment transport and topography during the period of 1960—2020, this study analyzed the relationship between the beach trough evolution and the elevation of channel water depth resources in the Jingjiang reach of the Middle reaches of the Yangtze River. The results indicate that after the operation of the Three Gorges Project, the scouring of the Jingjiang reach mainly occurred in the dry river channel, accounting for 90.97% of the total scour. The central bar area and point bar area was reduced by 18.3%, of which the area of the the central bar and point bars ware reduced by 9.4% and 24.9% respectively. Under the combined action of riverbed scouring and channel improvement projects, channel scale verification was carried out with 4.5 m×200 m (water depth ×width). The total length of navigation obstruction in Jingjiang reach accounted for 5.3% of the whole reach. The navigation obstruction characteristics of 4.5 m water depth were as follows: the decrease of dry water level in sandy pebble riverbed reach was higher than the undercut depth of river channel, resulting in insufficient water depth of channel. The scouring of convex bank and siltation of deep channel in concave bank, in sandy riverbed reach cause the instability of beach trough shape and channel boundary. Low flow route instability and insufficient water depth were caused by the shrinkage of the shoal and uneven scouring between the branching channels during the dry season. |
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