明渠砂质床面桩柱冲刷与导流防护试验研究

发布时间：2019-04-17 19:47

【摘要】：为了研究明渠砂质床面桩柱冲刷的水沙动力机理,分析极限平衡冲刷深度和范围随水流雷诺数的变化规律以及抗冲刷导流防护措施的效果,利用动床模型水槽试验,再现了桩柱周围局部床面从平整发展到冲刷坑的发育过程,测量了各工况下冲刷坑的形态参数,并利用PIV技术观测粗颗粒泥沙局部悬扬运动。结果表明:桩柱冲刷范围(相对于桩径D)随雷诺数ReD增大呈减小趋势。当雷诺数ReD在4 500~18 000之间变化时,冲刷深度变化范围为2.4D~1.3D,冲刷坑半径变化范围为4.5D~2.5D。砂质床面桩柱冲刷除存在显著的推移质运动外,还存在局部粗泥沙颗粒悬扬,且悬扬输沙的范围和强度随冲刷坑发展而强烈变化。在桩柱后方设置导流板能够有效抑制柱后卡门涡街的生成,桩后冲刷深度最大减小幅度为27.7%,但对柱前冲刷深度的影响不大。
[Abstract]:In order to study the water-sediment dynamic mechanism of sand bed pile scour in open channel, analyze the variation rule of limit equilibrium scour depth and range with Reynolds number of water flow and the effect of anti-scour diversion protection measures, the movable bed model flume test is used. The development process of the local bed surface around the pile from flatness to scour pit is reproduced. The shape parameters of the scour pit under various working conditions are measured, and the local suspended motion of coarse sediment is observed by using PIV technique. The results show that the scour range (relative to the diameter D) of the pile decreases with the increase of Reynolds number ReD. When Reynolds number ReD is between 4 500 and 18 000, the range of scour depth is 2.4 D / 3 D, and the radius of scour pit is 4.5 D / 2. 5D. In addition to the significant bed load movement, there are also local coarse sediment particles suspended, and the range and intensity of suspended sediment transport vary strongly with the development of scour pit. Setting a diversion plate behind the pile column can effectively restrain the formation of the Kamen vortex street behind the column. The maximum reduction of the scour depth behind the pile is 27.7%, but it has little effect on the scour depth in front of the column.
【作者单位】：天津大学水利工程仿真与安全国家重点实验室;山东新汇建设集团有限公司;
【基金】：国家自然科学基金创新研究群体项目(51621092);国家自然科学基金项目(51579175,51779172) 天津市科技支撑计划项目(16ZXCXSF00020)
【分类号】：TV149

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