不同流量下环翼型防冲板结构优化试验

为了研究不同流量条件下桥墩局部冲刷问题,在单片挡板基础上,增加防冲板数量形成了多级防冲结构。利用多元统计方法对防冲效果进行了主成分分析,认为最大冲坑深度最能体现试验效果,并以最大冲坑深度为指标进行试验分析。试验结果表明:在流量为75 m3/h时,增加防冲板数量并不能有效提升防冲效果;当流量增加到115 m3/h时,通过增加防冲板数量可在一定程度上提高桥墩的防冲能力,并且防冲效果随着防冲板间距的减小而增强,同时随着防冲板外径的增大而增强。但三级防冲板与二级防冲板防冲效果非常相近,第三级挡板对试验的结果影响甚微。因此,试验分析认为,在考虑不同流量条件下,环翼型防冲板最优防冲结构为两片防冲板,且防冲板外径为180 mm,间距取值为15 mm。

Experimental studies on structure optimization of ring-wing scour plates under different discharges

To carry out studies of the local scour around the bridge piers under different discharges, a multi-level structure is formed by increasing anti-scouring plates in addition to a single anti-scouring plate. A principal component analysis is made of anti-scouring indexes by multivariate statistical methods. It has proved the maximum pit depths have a great reflection of experiment results. In addition, the experiment results are analysed using the maximum pit depths. The analysis results show that the anti-scouring effect can′t be improved by increasing the anti-scouring plates at 75 m3/h, but it can be increased at 115 m3/h. Besides, the anti-scouring effect increases with decrease of the spacings between the anti-scouring plates, and enhances with increase of the outer diameters of the anti-scouring plates. However, the anti-scouring effect of three-level anti-scouring plates is similar to that of the two-level anti-scouring plates. The third-level anti-scouring plate has little effect on the experiment results. Therefore, under the conditions of different discharges, the optimal structure of the ring-wing anti-scouring plates will be two slices of the anti-scouring plates. The outer diameter of the anti-scouring plates is 180 mm, and the spacing between the anti-scouring plates is 15 mm.