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投稿时间：2021-07-16 修订日期：2022-05-24
投稿时间：2021-07-16 修订日期：2022-05-24
中文摘要: 弯曲河道水沙动力特性较顺直河道更加复杂，洪水流量与来沙条件变化改变弯道河床冲淤演变规律，影响漫滩洪水各项特性。本文开展了弯曲河道水槽模型试验，测量了不同水沙条件下弯道水面超高、河床地形、弯道水位和滩槽纵向流速，探究了水沙条件变化对弯曲河道河床冲淤演变和漫滩洪水特性的影响。对比了兰运长公式、张红武公式和毛佩郁公式对弯道水面横向超高的计算结果，发现兰运长公式具有更高的计算精度，该公式能更好地预测河床冲淤稳定后弯道最大水面超高。水流未漫滩时，泥沙补给变化对河床冲淤演变的影响较小，这是因为大部分补给泥沙沉积在上游顺直河段或被输运至弯道下游，仅有少量补给泥沙淤积在弯曲河段。洪水漫滩后，更多上游补给泥沙被输运至弯曲河段淤高河床。随着泥沙补给增大，弯曲河道主槽泥沙淤积量增大，河床小幅淤高，但对弯道水位和边滩流速的影响较小；洪水流量增大后，弯道水位和边滩水流流速显著增加；这表明洪水流量是影响弯道水位与边滩水流流速的主要因素，上游泥沙补给则是次要因素。对于洪水漫滩工况，90°弯道凹岸中断面附近（30°～60°）边滩水流流速相对弯道主槽和上游来流流速显著增大，其流速最大值出现在弯道50°断面，约为上游来流流速的1.3倍。研究成果对弯曲河道防洪减灾有重要意义。
Abstract:The dynamic characteristics of water and sediment in a meandering channel are more complex than that in a straight channel. The bed evolution and the characteristics of overbank floods in bend are affected by the changes of flood and sediment discharge. The laboratory experiment was carried out in a curved flume under several flow discharges and sediment supplies in this paper. The water surface elevation, bed topography, water level of bend and longitudinal velocities along the main channel and the floodplain were measured in detail, and the effects of flow discharges and sediment supplies on bed evolution and overbank floods in the meandering channel were discussed. The calculation results of Lan Yunchang formula, Zhang Hongwu formula and Mao Peiyu formula for the water surface superelevation of the curved channel were compared, Lanyunchang formula could better predict the water surface elevation of the curved reaches with stable bedform under different flow and sediment discharges. The sediment supply had little effect on bed evolution in bend with inbank flows, for that most of the sediment supply was deposited in the upstream straight reach or transported to the downstream reach and only a small amount of recharge sediment was deposited in the bend reach. More upstream sediment was transported to the curved reach and deposited by overbank flows. With the increase of sediment supply, the sediment deposition in the curved main channel increased, which however had little effect on the water level and flow velocity in bend. When the flood discharge increased, the water level in the bend and the flow velocity in the concave bank increased significantly. The results indicated that the flood discharge was the key factor affecting the water level in the bend and the flow velocity in floodplain, and the upstream sediment supply was the secondary influencing factor. The flow velocity in floodplain in the 30-60° of 90° bend reach was higher than that in the main channel and upstream reach. The maximum flow velocity in the floodplain occurred in section 50°, which could reach 1.3 times of the upstream flow velocity. The above results are of great significance for flood control and disaster reduction of meandering rivers.
文章编号：202100695 中图分类号：TV142 文献标志码：
基金项目:教育部霍英东教育基金会青年教师基金项目（171067）；教育部交流合作项目（教外司人文2020-703-3）；长江联合基金项目（U2040219）
作者简介:第一作者：王奇（1997—），男，硕士生. 研究方向：河流泥沙及河床演变. E-mail：599953159@qq.com;通信作者：刘超, E-mail：liuchaoscu@vip.qq.com
引用文本：
王奇,单钰淇,刘超,刘兴年.不同水沙条件下弯道河床冲淤与漫滩洪水特性研究[J].工程科学与技术,2022,54(5):158-167.
WANG Qi,SHAN Yuqi,LIU Chao,LIU Xingnian.Study on Characteristics of Bed Evolution and Overbank Floods in Meandering Channel Under Different Water and Sediment Discharges[J].Advanced Engineering Sciences,2022,54(5):158-167.
引用文本：
王奇,单钰淇,刘超,刘兴年.不同水沙条件下弯道河床冲淤与漫滩洪水特性研究[J].工程科学与技术,2022,54(5):158-167.
WANG Qi,SHAN Yuqi,LIU Chao,LIU Xingnian.Study on Characteristics of Bed Evolution and Overbank Floods in Meandering Channel Under Different Water and Sediment Discharges[J].Advanced Engineering Sciences,2022,54(5):158-167.