山区河流上下双丁坝回流区的水沙特性试验研究

发布时间：2018-05-22 14:09

本文选题：上下双丁坝 + 模型试验　；参考：《重庆交通大学》2017年硕士论文

【摘要】：在航道整治建筑物中,丁坝以不同的坝体结构或者布置形式被广泛利用到需要不同程度治理的航道中。对于山区河流应经济发展和河流稳定性的要求,与单丁坝相比较,上下双丁坝的布置形式能够更好地发挥它的优势,有更好的整治效果。但是双丁坝的回流呈现的三维紊动特性比单丁坝的紊动特性还要复杂,而且下丁坝的阻拦造成上下双丁坝回流的泥沙淤积情况也更加严重,对河流形态和通航情况造成一定程度上的影响。所以对于山区河流上下双丁坝回流区的水沙特性的研究对于整治山区河流的航道的稳定性和通航条件都有十分重要的意义。本文以长江上游叙渝段航道建设工程为研究背景,以交通运输部科技项目“长江上游航道整治建筑物水毁及监测修复技术研究”为依托,在调查统计整治建筑物水毁情况的基础上,有针对性地进行了上下双丁坝清水定床试验,对上下双丁坝回流区的水沙特性进行了探索性的分析。本文在利用超声多普勒流速仪(ADV)对物理模型的双丁坝附近的三维流速进行测定,并根据所测的实验数据得到紊动强度和水流紊动能。根据绘制得到的丁坝下游附近的平面流速图分别划分上下丁坝下游的流区范围,得到上丁坝主流区和回流区,以及下丁坝下游主流区和回流区。再将回流区从横向上划分为正流区和负流区,沿纵向上把回流区分为增流区和减流区。并研究了不同坝间距和不同长坝组合因素对双丁坝下游各流区划分的影响:下丁坝的坝长的增加会导致上下双丁坝回流区的范围都增大,而且下丁坝下游的回流长度也会增大;坝间距的减小却会致使下丁坝的回流区增大,而且下丁坝的回流长度也会增大。根据紊动速度、紊动强度以及水流紊动能在各流区的分布曲线图,得到回流区的紊动强度整体上都比主流区的紊动强度要大,而且主要是纵向上的紊动强度在各流区的改变范围是最广的,根据纵向紊动强度的沿程变化,发现可以拟合得到各流区的相对纵向紊动强度沿程变化公式。在不考虑推移质的情况以及一定假设基础之上,基于K方程,得到适用于下丁坝下游各流区的水流挟沙能力公式,反映水流挟沙力在时均速度的变化下的沿程改变,并分析了时均速度和沿程变化对双丁坝下游回流区的冲淤影响。
[Abstract]:In waterway regulation buildings, spur dams are widely used in waterways with different dam structure or arrangement. The arrangement of upper and lower double spur dams can give better play to its advantages and have better remediation effect compared with single spur dams in accordance with the requirements of economic development and river stability of mountain rivers. However, the three dimensional turbulent characteristics of the return flow of double spur dams are more complicated than that of single spur dams, and the siltation of backflow of lower and lower spur dikes is more serious than that of single spur dams. To a certain extent, the river shape and navigation conditions are affected. So it is very important to study the characteristics of water and sediment in the backflow zone of the upper and lower groins of mountain rivers for regulating the channel stability and navigation conditions of mountain rivers. This paper takes the waterway construction project in the upper reaches of the Yangtze River as the research background, and relies on the scientific and technological project of the Ministry of Communications and Transport, "the Research on Waterway damage and Monitoring and Restoration of Waterway in the Upper reaches of the Yangtze River". On the basis of the investigation and statistics of the water damage situation of the renovated buildings, the water bed fixing test of the upper and lower double spur dams is carried out, and the characteristics of the water and sediment in the backflow zone of the upper and lower double spur dams are analyzed in an exploratory way. In this paper, the three-dimensional velocity near the double spur dam of the physical model is measured by using the ultrasonic Doppler velocimeter (ADV), and the turbulence intensity and the turbulent energy of the flow are obtained according to the measured experimental data. According to the plane velocity diagram of the lower reaches of the spur dike, the flow area of the lower and lower dikes is divided into the upper and lower dikes, and the upper and lower groyne flow regions are obtained as well as the lower groyne downstream and the lower groyne flows. The circumfluence zone is divided into positive flow region and negative flow zone laterally, and the reflux region is divided into increasing flow region and decreasing flow region along the longitudinal direction. The influence of different dam spacing and different combination of long dams on the division of the downstream flow zones of Shuang spur dam is studied. The increase of the dam length of the lower spur dike will result in the increase of the range of the return zone of the lower and lower groyne dams, and the return length of the downstream of the lower spur dike will also increase. The decrease of the spacing will increase the return zone and the length of the return in the lower spur dike. According to the distribution curves of turbulence velocity, turbulence intensity and turbulent energy in each flow region, the turbulence intensity in the reflux region is larger than that in the mainstream region. It is found that the relative longitudinal turbulence intensity variation formula can be obtained according to the variation of longitudinal turbulence intensity. Based on the K equation and without considering the bed load, the formula of sediment carrying capacity is obtained, which can reflect the variation of the sediment carrying capacity along the flow under the change of the time average velocity. The influence of the time average velocity and the variation along the course on the scour and deposition of the backflow zone in the lower reaches of the double spur dam is analyzed.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U617.91

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