| 朱博渊,刘 涛,谢景彧,李 赟,王敬文,高月星.沅水尾闾金石垸、太湖垸采砂对航道水流条件的影响*[J].水运工程,2025,(1):93-101 |
| 沅水尾闾金石垸、太湖垸采砂对航道水流条件的影响* |
| Impact of sand mining of Jinshi and Taihu embankments at lowest reach of Yuanjiang River on hydrodynamics of nearby shipping channel |
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| DOI： |
| 中文关键词: 沅水尾闾 分汊河道 采砂 锁坝 航道 数学模型 |
| 英文关键词:the lowest reach of Yuanjiang River bifurcating channel sand mining blocking dam shipping channel numerical model |
| 基金项目:国家自然科学基金资助项目（52209079）；
流域水循环模拟与调控国家重点实验室开放研究基金项目（IWHR-SKLKF202211）；
湖南省自然科学基金资助项目（2021JJ40607） |
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| 中文摘要: |
| 分汊河段内采砂易改变汊道原有分流比，进而影响航道水流条件，危及主航道通航安全。为研究沅水尾闾金石垸、太湖垸采砂对航道水流影响，采用2016、2022年实测地形与水文资料，构建平面二维水流运动数学模型，计算采砂前后不同地形和水文条件下水动力场变化。结果表明，研究河段滩槽形势稳定，采砂不会引起主航道尺度明显变化和泥沙淤积；若采砂后中汊锁坝被冲毁，中汊分流比增大7.12%以上；采砂后主航道最小水深仍大于3 m，满足通航要求，锁坝封堵使得河段进口至汊道分流口水面比降减小4‰。若采砂后锁坝被冲毁，枯水期主航道水位最大下降0.10 m；采砂前后河段流场整体变化不大，采区附近流速变小，局部流速最大偏转角小于23°，不影响采砂船进出；锁坝封堵使得洪水期中汊流速减小0.52 m/s。锁坝对稳定总体河势起控制作用，可避免中汊冲刷发展造成主航道水位陡降、尺度萎缩甚至改线，同时采区边界附近流速较大、冲刷滩地，建议对锁坝和滩地进行守护。 |
| 英文摘要: |
| Flow partition ratios of branching channels are easily altered by sand mining activities in bifurcating reaches,which affects flow conditions of shipping channels and may threaten navigation safeties.To investigate the impact of sand mining in Jinshi and Taihu embankments at the lowest reach of Yuanjiang River on hydrodynamics of nearby shipping channel,we use data of riverbed terrain and hydrology in 2016 and 2022 to establish numerical model of planar 2D flow motion,from which hydrodynamic changes are calculated for different terrain and hydrology combinations before and after sand mining.The results show that beach-channel regime is stable in the study reach,and no obvious change of the navigation-channel dimension and sediment deposition is triggered by sand mining.The flow partition ratio of the middle branch will be enhanced by larger than 7.12% if blocking dams within this branch are destroyed by rush of water after sand mining.The minimum water depth in the navigation channel is still larger than 3 m after sand mining,which meets the navigation requirement.The blocking dams reduce the water surface slope by 4‰ between the entrances of the study reach and the bifurcating area.If blocking dams are destroyed after sand mining,water level along the main shipping channel will drop by 0.10 m in dry season.The whole flow field changes little before and after sand mining.Flow velocities around the two embankments decrease and the maximum deflection angle is smaller than 23°,which do not hamper sand dredger access.Blocking dams reduce flow velocity in the middle branch by 0.52 m/s in wet season.Blocking dams control the overall stability of river regime and prevent the middle branch from erosion and development which might lead to steep water-level drop,dimension shrinkage and even rerouting in the shipping channel.Meanwhile,high flow velocities occur around mining area boundaries and scour beaches,so it is recommended to protect the blocking dams and beaches. |
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