变截面方形桥墩折冲效果数值模拟

Numerical simulation of effect of reducing erosion around square piers with variable section

为研究方形桥墩截面变化对局部冲刷特性的影响,通过建立桥墩局部冲刷三维数学模型,对方墩前端不同伸出台阶宽度及相应倾斜坡度情况下的冲刷特性展开模拟研究。结果表明:相较于方墩,墩前伸出一定台阶宽度的结构形式具有较好的折冲效果,但其折冲效果并非随着伸出宽度的增加而增加,墩前伸出台阶宽度约在墩宽的2/3时折冲效果最优;同时,通过在伸出台阶宽度基础上增加倾斜坡面的截面优化处理,得出倾斜坡面高度在床面以上0.4h(h为水深)情况下,随着台阶伸出宽度的增加其折冲效果呈增加趋势,且具有比仅伸出台阶宽度的截面结构形式更优越的折冲效果,最大折冲率高达38%。研究结果可为桥墩结构形式与抗冲防护的综合研究,尤其是大型桥墩基础结构的优化提供参考。

In order to study the influence of the cross section variation of a square pier on local scour characteristics,we established a 3D mathematical model of the local scour around the pier and carried out a simulation study on the scour characteristics around the square pier under different stepped protruding widths and corresponding slopes.The results show that compared with the square pier,the structure with a certain stepped protruding width in front of the pier has a certain effect on scour reduction,but the effect does not increase with the increase of the protruding width,and the effect is optimal when the protruding width in front of the pier is about 2/3 times of the width of the pier.At the same time,through the stepped protruding width,the inclined slope surface is increased based on section optimization.It is concluded that with the increase of the protruding widths,its reduction effect increases with inclined slope height under the condition of bed surface more than 0.4 times of the water depth,the effect of which is superior to the structure of the protruding widths and its maximum reduction rates are as high as 38%.The results can provide a reference for the research on the integration of pier structure form and scour protection,especially for the optimization of large-scale pier foundation structures.