权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The study on control of sand bars and bank erosion in meandering rivers

曲流河道沙坝及河岸侵蚀治理研究

基本信息

批准号：
07455196
负责人：
MURAMOTO Yoshio
金额：
$ 4.54万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455196/
关键词：
meandering river sand bar bank erosion channel process 流路変動画像解析数値解析河岸浸食

项目摘要

In the meandering river, the high velocity filament is shifted toward near the side bank and it leads to bank erosion. Disaster caused by the river bank erosion creates serious problems such as the people nearby homeless and the failure of river structures. Many disasters caused by the above situation have been reported. Therefore, it is important to make clear the mechanism of channel processes with bank erosion from disaster prevention point of view.At first, image processing of Landsat TM data was applied to survey river channel changes. The year to year changes of river channels, erosion areas, deposition areas and bars were clearly visualized by the processing technique. Based on the results, the characteristics of the channel process and an influence of flood magnitudes upon them were examined.Next we performed the experiments using the same sine-generated plan from having identical uniform sediment, whereas, the hydraulic condition was different in each of the cases. The morphol … More ogical processes were different in accordance with the imposed hydraulic condition.Finally, we developed a numerical model which can be used for both bed deformation and bank line shifting in 2-D plan form. The model was applied to the morphological behavior of experimental channels and actual rivers. In the case of experimental channels, the fundamental equations in a moving boundary fitted coordinate system are used, and the formulation of non-equilibrium sediment transport also is introduced to reproduce the phenomena accurately. Temporal changes in the plan form in a meandering channel are classified into two patterns of meander developing and straightening. Comparison of the observed and calculated results verified that the model is applicable to both channel processes under various hydraulic conditions. The initial development of meandering from a straight plan form also was analyzed using the model to clarify the effect of alternate bars on bank erosion. Lastly, the model was modified for the calculation of actual river processes with bank erosion. On the basis of the numerical findings, we discuss the effects of such hydraulic variables as the velocity distributions along the bank on the location of bank erosion and bed scouring. Less

在蜿蜒的河流中，高速细丝向岸边移动，导致岸坡冲刷。河岸侵蚀造成的灾害造成了附近居民无家可归、河道建筑物破坏等严重问题。上述情况造成的多起灾害已有报道。因此，从防灾的角度弄清河道冲刷过程的机理具有重要意义。首先，将陆地卫星TM数据的图像处理应用于河道变化调查。该处理技术清晰地显示了河道、冲刷区、淤积区和沙洲的年际变化。在此基础上，分析了河道过程的特点以及洪水强度对河道过程的影响。其次，在相同的均匀泥沙条件下，采用相同的正弦生成方案进行了试验，但不同情况下的水力条件不同。The Morphol…根据所施加的水力条件，更多的数学过程是不同的。最后，我们建立了一个二维平面形式的河床变形和岸线移动的数值模型。该模型被应用于实验河道和实际河流的形态特性。对于实验航道，采用动边界拟合坐标系中的基本方程，并引入了非平衡输沙公式，以准确再现这一现象。曲流河河道平面形态的时间变化可分为曲流河发育和拉直两种模式。实测结果与计算结果的对比表明，该模型适用于不同水力条件下的两种航道过程。利用该模型分析了曲流滩由平直形态演变而来的初步演变过程，以阐明交替沙洲对岸坡冲刷的影响。最后，对该模型进行了修正，使之适用于有岸坡侵蚀的实际河道过程的计算。在数值结果的基础上，讨论了流速分布等水力变量对岸坡冲刷和河床冲刷位置的影响。较少