丁坝设计参数对河床冲淤量的影响规律研究

Study on influence law of groin design parameters on riverbed scouring and siltation

天然河道中修建丁坝后,丁坝附近的流速场会出现新的变化。流速变大的区域,局部冲刷加剧,危及丁坝自身的安全;流速减小的区域,泥沙在坝后沉积,形成淤积区,可起到保护下游河岸的作用。在总结前人研究成果的基础上,通过室内动床试验,利用Sufer软件的体积计算功能,就丁坝设计参数的变化对河床的冲淤量影响规律进行了深入研究。结果表明:冲淤量均随坝长的增加而增加,但坝后淤积量增加幅度大于冲刷量增加幅度;相比正交丁坝,在其他条件不变时,随着挑角的减小,非正交丁坝的冲刷量和淤积量都有减小的趋势,且冲刷量的减小趋势远大于淤积量的减小趋势。

Once a groin is built in the natural river, new changes of the flow velocity field around the groin may appear as follows： local scouring intensified in the zone of flow velocity increased, endangering the groin safety; while sediment deposited behind the dam in the zone of flow velocity decreased, forming a sedimentation area. On the basis of previous research achievements, and by using the volume calculation function of Sufer, the influence of groin design parameters on riverbed scouring and siltation was explored according to movable bed experiment. The study results show that the scouring and siltation increases as the length of groin increases while the increasing extent of siltation is greater than that of scouring. Moreover, under otherwise equal conditions, the scouring and siltation of orthogonal groin decrease with the reduction of bucket - slip angle, and the decreasing tendency of scouring is much greater than that of siltation.