摘要
由于传统桥墩冲刷防护技术的局限性,引入环翼型防冲板和开缝组合的新型防护措施,通过主动减小墩前下降水流和墩侧绕流对河床进行防护。为探究组合防护措施的防冲刷效果,采用最优安装位置、最优形状的防冲板与不同高度、不同位置的墩缝系统组合,进行室内物理模型试验。以冲坑三维特征、桥墩周围时均流速、紊动强度和紊动动能作为试验指标,定量分析开缝防护与组合防护对桥墩冲刷的影响。试验结果表明:两类防护下,冲坑深度均显著减小,且组合防护的冲坑深度减小率是开缝防护的1.8倍;组合防护下,墩前垂向时均流速、垂向紊动强度和紊动动能都明显减小,并在防冲板位置出现板上值远大于板下值的突变现象,墩侧纵向时均流速和纵向紊动强度减小效果显著。研究表明,对于圆柱形桥墩的局部冲刷,环翼型防冲板和开缝组合防护效果突出,为深入研究桥墩防冲刷的组合防护奠定了一定的基础。
A new anti-scour device of slotted piers with a semicircular fin is presented in this paper to overcome the limitations of traditional technologies for better protection of bridge piers from local scour. This device protects riverbed by reducing the flow around the piers and its scour power. To examine the scour reduction, we have conducted laboratory tests on a scale model of a cylindrical bridge pier, using different shapes and sizes of the semicircular fin and its different installation heights combined with different locations of the pier slot. And the scour reducing effects were eveluated and analyzed by measuring the 3D geometrical characteristics of the scour pits around the piers, along with the average velocity, turbulence intensity, and turbulent kinetic energy of the flow around the piers. The results showed that scour depth was significantly reduced by the new device and its reduction in scour depth was 1.8 times greater than that by opening a slot on the pier only. And in front of the piers, the mean values of vertical average velocity, vertical turbulence intensity, and turbulent kinetic energy were all decreased obviously, with the values above the fin plate far larger than those under it. At both sides of the piers, mean longitudinal velocity and longitudinal turbulence intensity were also reduced remarkably. Thus, the device of a slotted cylindrical pier with a semicircular fin has prominent anti-scour effect and provides a basis for further studies and engineering application.
出处
《水力发电学报》
EI
CSCD
北大核心
2017年第4期26-37,共12页
Journal of Hydroelectric Engineering
基金
国家自然科学基金(51369022)
内蒙古自然科学基金(2013MS0719)
黄河水利科学研究院基本科研业务费项目(HKY-JBYW-2016-34)
关键词
环翼型防冲板
开缝
组合防护
冲坑三维特征
时均流速
紊动强度
紊动动能
anti-scour semicircuar fin
slotted pier
combined preventive measure
3D characteristics of scour pit
time-average velocity
turbulence insensity
turbulence kinetic energy
作者简介
牟献友（1969-），男，教授．E-mail：mouxianyou@163．com
通信作者：冀鸿兰（1970-），女，教授．E-mail：honglanji@sina．com
