圆端形桥墩的新型防护措施研究

发布时间：2018-01-08 14:27

本文关键词：圆端形桥墩的新型防护措施研究　出处：《内蒙古农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：桥梁灾害发生的主要原因是水流冲刷桥墩造成桥墩的水毁,因此,研究桥墩周围的水流结构和其发展历程是十分重要的。由于传统桥墩防护措施的局限性,课题组引入新型防冲装置-环翼式防冲板,对桥墩进行防护。其防冲的主要原理,通过改变桥墩周围的水流结构,主动降低下了降水流对桥墩的冲刷。本文基于前人在圆柱形桥墩上安装环翼式防冲板进行防护的试验,对圆端形桥墩安装环翼式防冲板进行研究。试验采用了 3种流量-水位、3种长宽比不同的圆端形桥墩、3种防冲板安装高度、2种防冲板形状进行物理模型试验。试验中,测量冲刷坑的深度、长度、宽度、墩周的垂向瞬时流速。通过处理数据,分析冲坑三维特征、Surfer地形图、时均垂向流速、垂向紊动强度、紊动切应力等,探究安装环翼式防冲板后,桥墩周围的水力特性以及防冲刷效果。综合以上分析,得出以下结论:(1)圆端形桥墩安装防冲板后,墩前冲刷坑的深度、长度、宽度明显减小,墩前冲刷坑深度减小率最高达30.43%;(2)选取半幅防冲板、防冲板安装位置在1/3水深处,防冲效果最佳;(3)应用Surfer软件模拟圆端形桥墩墩前冲刷坑形态,冲刷坑深度明显减小;(4)安装环翼式防冲板后,3种长宽比不同的桥墩,墩前中间测线的垂向时均流速均明显减小;(5)中圆端形桥墩墩周垂向紊动强度的分布与垂面紊动切应力的分布大体相同;安装防冲板后,墩前中间、墩后中间测线的垂向紊动强度与垂面紊动切应力明显减小。
[Abstract]:The main cause of bridge disaster is the water damage caused by water flow scouring the pier. Therefore, it is very important to study the flow structure and its development course around the pier, because of the limitation of the protection measures of the traditional pier. The research group introduces a new type of anti-scour device, ring wing anti-scour plate, to protect the pier. The main principle of anti-scour is to change the structure of water flow around the pier. This paper is based on the experiments of installing annular wing anti-scour plates on cylindrical piers in this paper. This paper studies the installation of annular wing type anti-scour plate for round end pier. Three kinds of installation height of round end pier with different ratio of discharge to water level and different aspect ratio are used in the test. In the experiment, the depth, length, width, vertical instantaneous velocity around the pier of the scour pit were measured. Through processing the data, the three-dimensional characteristics of the scour pit were analyzed. Surfer topographic map, time average vertical velocity, vertical turbulence intensity, turbulent shear stress, etc., to explore the hydraulic characteristics and scour prevention effect around the pier after installing the annular wing anti-scour plate. The following conclusions are drawn: (1) the depth, length and width of the scour pit in front of the pier are obviously reduced after the anti-scour plate is installed on the round end pier, and the maximum reduction rate of the depth of the scour pit in front of the pier is 30.43; (2) the best anti-scour effect is obtained by selecting half of the anti-scour plate and installing the anti-punching plate in the depth of 1/3 water; The Surfer software is used to simulate the shape of the scour pit in front of the round end pier, and the depth of the scour pit is obviously reduced. 4) after installing the annular wing type anti-impact plate, the vertical average velocity of the midline in the front of the pier is obviously reduced in three kinds of piers with different aspect ratio; (5) the distribution of the vertical turbulent intensity around the pier is approximately the same as that of the vertical turbulent shear stress. The vertical turbulence intensity and the vertical turbulent shear stress of the measured lines in the front and back of the pier are obviously reduced after the anti-punching plate is installed.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U443.26

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