适用于中小河流受损岸坡修复的楔形丁坝群水力特性初探

河道内流动控制结构物作为一种主动防护型的护岸型式,以其特有的生态效益,伴随着河流治理理念由渠化向河流再自然化的回归,日益成为新的研究热点。在归纳总结国内外常见河道内流动控制结构物分类和作用特性的基础上,选取逆水流方向布置的楔形丁坝为研究对象,采用三维数值模拟方法对布置楔形丁坝群前后193°强弯曲水槽内的三维水力特性进行对比分析,初步分析弯曲水槽内楔形丁坝群的作用机制和挑流效果。研究结果表明:楔形丁坝群主要通过调整弯道内的二次流结构,达到将高流速水流挑离凹岸、避免岸坡遭受冲蚀的目的;楔形丁坝群布置会造成弯道内水位雍高,高流速水流向凸岸一侧偏移,其雍水高度和偏移程度与楔形丁坝群的布置方式密切相关。研究成果对于河流生态修复领域生态水工结构物相关研究的开展与深化具有借鉴意义。

Preliminary Study on Hydraulic Characteristic of Stream Barbs forEcological Restoration of Medium and Small Rivers

As river restoration idea transfers from canal-dominated back to nature-oriented, instream flow control structure, as a proactive bank protection measure, is drawing increasing attention due to its unique ecological benefits. The main categories, working characteristics, applicability and research progress of in-stream flow control structure in China and abroad are summarized in this paper.On this basis,the 3D hydraulic characteristics in a 193° sharp bending flume before and after stream barbs are arranged in backflow direction are studied and comparedthrough numerical simulation. The working mechanism and effectiveness of stream barbs in bend flume are investigated preliminarily. Results demonstrate that stream barbs could achieve the purpose of bank stabilization by adjusting the secondary flow structure and deflecting the high speed flow far away from the concave bank. Nevertheless, stream barbs would give rise to backwater in the bend and deviate the high speed flow on the convex bank side. The backwater level and deviation degree are closely related with the layout pattern of stream barbs. The study is of referential significance for upcoming researches on eco-hydraulic engineering structures in river ecological restoration field.