丁坝挑角对180°弯道生态河床的影响  

The Effect of the Pick Angle of Spur Dikes on the Ecological Riverbed Evolution Within a 180°Bend

作　　者：刘丹丹 吕岁菊 李春光 LIU Dan-dan;LÜSui-jü;LI Chun-guang(School of Civil and Hydraulic Engineering,Hefei University of Technology,Hefei 230009,Anhui Province,China;School of Civil Engineering,North Minzu University,Yinchuan 750021,Ningxia Province,China;School of Mathematics and Information Science,North Minzu University,Yinchuan 750021,Ningxia Province,China)

机构地区：[1]合肥工业大学土木与水利工程学院,安徽合肥230009 [2]北方民族大学土木工程学院,宁夏银川750021 [3]北方民族大学数学与信息科学学院,宁夏银川750021

出　　处：《中国农村水利水电》2024年第12期90-100,共11页China Rural Water and Hydropower

基　　金：宁夏自然科学基金资助项目(2023AAC03296,2023AAC02050);国家自然科学基金资助项目(11861003)。

摘　　要：丁坝的合理布局有效地调整了水流结构和河床冲淤形态,不仅起到护岸作用,同时在丁坝附近形成的深潭、浅滩等多样化的河床,为水生生物提供丰富的栖息地,促进生态可持续发展。基于CFD技术,采用RNGk-ε模型进行参数率定验证,对180°弯道凹岸处不同挑角的丁坝单元附近的水流动力学特性及河床冲淤演变展开深入研究。结果表明,在能量损失和水位变化方面,正挑丁坝表现最为显著,水位差最大,能量损失亦最为严重;上挑丁坝次之,下挑丁坝最小。涡旋强度与河床冲淤程度呈正相关关系,其中逆时针涡旋促进淤积,顺时针涡旋易引起冲刷。在切应力分布方面,坝头处及丁坝对岸形成的强切应力区的范围和强度呈现正挑丁坝最大、上挑丁坝次之、下挑丁坝最小的规律。由此可见,丁坝挑角的选择对河床冲淤、水流特性及生态效应具有深远的影响。科学合理地设计与布置丁坝,是实现河床冲淤控制、河道生态平衡维护与工程安全共赢的关键所在。The rational layout of spur dikes has a significant impact on the flow structure,patterns of fluvial erosion and deposition.In addi⁃tion to serving as a protective measure for riverbanks,these dikes also play a role in promoting the formation of various riverbed features,such as deep pools and shallow shoals nearby.These unique characteristics create a rich habitat for aquatic organisms,thereby enhancing ecological sustainability and development.Using the computational fluid dynamics(CFD)technique and the RNG k-εmodel for parameter calibration and verification,this study undertakes a rigorous investigation into the hydrodynamic properties and the fluvial erosion-deposi⁃tion processes occurring in the vicinity of spur dike units with diverse deflection angles situated at the concave bank of a 180°bend.The re⁃sults indicated that,in relation to energy dissipation and water level fluctuations,the spur dike with a 90°deflection angle exhibited the most prominent characteristics,yielding the greatest water level disparities and the most significant energy losses.The spur dike exhibiting an up⁃ward deflection angle occupied a secondary position,whereas the spur dike with a downward deflection angle demonstrated the least noteworthy effects.Furthermore,a positive correlation was identified between vortex intensity and the degree of riverbed erosion and deposition.Counterclockwise vortices contributed to deposition,whereas clockwise vortices were prone to cause erosion.In terms of the distribution of shear stress,the scope and magnitude of the intense shear stress zones formed at the head of the spur dike and on the opposite bank exhibit a distinct pattern where the spur dike with a 90°deflection angle shows the largest impact,followed by the upward deflection spur dike,and the downward deflection spur dike demonstrates the smallest impact.So,the selection of deflection angles for spur dikes significantly influ⁃ences riverbed scouring and deposition,water flow characteristics,and ecological outcomes.It is c

关 键 词：丁坝 数值模拟 环流结构 剪切应力 生态河床 

分 类 号：TV854[水利工程—水利水电工程]