A Study on Sediment Transport and River Bed Variation Based on the Simultaneous Measurements of Flow and Sediment Movement in Various Scales

本研究借助各种新技术，通过对流沙运动的同步测量，阐明了包括实验室水槽和野外河流在内的不同尺度下，漩涡悬浮泥沙、河床形态、输沙量和泥沙分选等泥沙输运和河床变化的机制。该工作已作为与日本土木工程师学会水力学委员会工作组的联合研究推进。1991年12月，两个小组联合举行了一次“同时测量水流和泥沙输送”的小型讨论会。Nezu利用双分量激光风速仪和水位计在实验室水槽中测量了沙丘上非定常流的湍流结构，发现洪水上升阶段的湍流强度和悬沙浓度高于下降阶段。萨瓦伊设计了一种利用个人计算机自动测量任意曲线河床形态的新技术，并阐明了在洪水期间曲流河道河床形态变化的特征，在曲流河道中没有发现明显的河床高度变化。池田在大型实验室水槽中阐明了纵向泥沙分选，并讨论了黄河岩质河床的作用。他还强调了磨蚀作用对河道泥沙粒度变化的影响。Sawada和Ashida通过对金祖河asharaidani流域的长期观测，阐明了山溪泥沙径流的特征。研究发现，流域输沙量的变化与河流的变化高度相关。他们还考虑了在未来的观察中测量的内容和准确度。长谷川、木下、西田、富永等人通过对石kari河、Shiribetsu河、Takase河和Gumma灌渠等地的观测，阐明了低地河流的洪水流量和输沙情况。通过富永的工作，确定了实验室水槽与野外河流之间流动结构的相似性。Nishida等人设计了一种新的技术，利用桥旁的一对绳索来支撑探测器，并在河口附近观察了盐度和速度场的变化。长谷川在石kari河河口附近同时观测流速和悬沙，发现剪切速度和含沙量峰值出现在水位峰值之前。木下尝试利用悬停飞行器和流动浮标快速测量床型，找到了一系列波长比约为6的床型。少

In this study, the mechanism of sediment transport and river bed variation such as suspension of the sediment by eddies, bed configuration, sediment discharge and sediment sorting with various scales including laboratory flumes and field rivers are clarified through simultaneous measurements of flow and sediment movement with the help of various new techniques. This work had been promoted as the joint research with the Working Group of Hydraulics Committee of Japan Society of Civil Engineers. In December, 1991, a mini-symposium "simultaneous measurements of flow and sediment transport" was co-held by the both groups. The results obtained by each investigator are summarized as follows:Nezu measured the turbulent structure of unsteady flow on dunes in a laboratory flume, using two component laser anemometer and water level gage, and found that the turbulence intensity and suspended sediment concentration are higher in the rising stage than in the descending stage of a flood.Sawai devised … More a new technique to measure a bed form along arbitrary curves automatically using a personal computer and clarified the characteristics of the bed variation in a meandering channel during a flood, in which no remarkable variation of bed level was found.Ikeda clarified the longitudinal sediment sorting in a large scale laboratory flume and discussed about the effect of rocky stream bed in River Ooi. He also emphasizes about the role of abrasion on the sediment size variation along river courses.Sawada and Ashida clarified the characteristics of the sediment runoff in a mountain stream through long term observation in Ashiaraidani basin of Jinzu River. It was found that the variation of sediment discharge is highly correlated with stream variation. They also considered about what and how accurate to measure in future observation.Hasegawa, Kinoshita, Nishida and Tominaga clarified the flood flow and sediment transport in low land rivers through observation in River Ishikari, River Shiribetsu, River Takase and Gumma Irrigation Channel etc. Through Tominaga's work, the similarity of flow structure between laboratory flumes and field rivers was ascertained. Nishida et. al devised a new technique to support the probes using a pair of ropes beside a bridge and observed the variation of salinity and velocity field near a river mouth. Hasegawa observed the flow velocity and suspended sediment simultaneously near the mouth of River Ishikari and found that the peak of shear velocity and sediment concentration appears before that of the water level. Kinoshita tried to utilize a hover craft and a flowing buoy to measure bed profile quickly and found out a series of bed forms with the wave length ratio about 6. Less