为探究滦河下游丁坝群对水流特性影响及坝头冲刷变化情况,利用Flow 3D建立了滦河下游腰庄段丁坝群三维水沙模型,采用2015年实测数据对模型进行了验证。模拟了5 a一遇和10 a一遇恒定流与非恒定流工况下丁坝群坝头流速分布及局部冲刷。结果表明,丁坝群能够有效减缓水流流速,改善水流对河岸的侵蚀,对滦河下游腰庄河岸起到保护作用。在恒定流条件下,10 a一遇工况较5 a一遇主流最大流速区逐渐偏向右岸,同时受主流冲击的丁坝流速增加约1.7 m/s,其余丁坝流速增加约0.9 m/s。在行洪过程中,受主流冲击的典型丁坝坝头产生了明显的冲刷坑,其中丁坝冲刷坑形态呈沿水流方向的狭长带状。随着重现期的增加,典型丁坝坝头冲刷坑深度增加约1 m,同时丁坝坝头冲刷带开始向上游延伸。研究成果可为丁坝局部冲刷安全分析提供参考。
Abstract
To investigate the impact of spur dike groups on water flow characteristics and local scour in the lower reach of the Luanhe River, a three-dimensional water and sediment model is constructed by using Flow 3D software. The model’s accuracy is validated using measured data in 2015. Simulations are conducted under both constant and unsteady flow conditions, considering 5-year and 10-year return periods, to analyze flow velocity distribution and local scour at groin head. Findings demonstrate that the spur dike group effectively reduces flow velocity, enhances river bank resistance to water erosion, and protects the river banks of Yaozhuang segment in the lower reaches of the Luanhe River. Under constant flow, the maximum velocity zone of the main stream gradually shifts towards the right bank during the 10-year return period, compared to the 5-year return period. Moreover, the velocity at groins impacted by the mainstream increases by approximately 1.7 m/s, while the flow velocity at the head of other groins rises by around 0.9 m/s. During flood discharge, typical groin head subjected to the mainstream experiences noticeable scour pits assuming a long and narrow strip shape aligned with the water flow direction. Additionally, with longer return periods, the depth of the scour pit at the head of a typical spur dike increases by about 1 m, and meanwhile the scour zone at groin head starts to propagate upstream.
关键词
丁坝群 /
水沙模型 /
局部冲刷 /
水力特性
Key words
spur dike group /
water and sediment model /
local scour /
hydraulic characteristic
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基金
国家自然基金创新群体研究项目(51621092)
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