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Evaluation technique for erosion rate of cohesive sediment and its application to the geomorphological

粘性沉积物侵蚀速率评价技术及其在地貌中的应用

基本信息

批准号：
17560463
负责人：
SEKINE Masato
金额：
$ 0.83万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

Erosion process of cohesive sediment was investigated experimentally in this study. Fundamental studies had been already conducted in the experimental flume to evaluate the erosion rate of uniform cohesive sediment. In this study, we developed a movable apparatus of erosion test, which was designed to conduct a field measurement of erosion rate of naturally deposited cohesive sediment. We also established the experimental techniques for such a measurement. Several series of measurements were conducted in large-scale open-air experimental flume in order to check the validity and utility of this apparatus. It was verified that the results had almost same order of accuracy as that by our standard test in laboratory. This is one of the main achievements of this study.The effect of cohesiveness of sediment on the erosion process of bare-slope was also investigated here. This is the second part of this study. Experiments were conducted to investigate the geomorphological change in model bare slope, which was constituted by cohesive sediment, due to an artificial rainfall. Before doing that, the information about the experimental technique of erosion test of cohesive sediment by us was instructive. Clay content ratio is only the parameter to be changed in this series of experiments. It was seen that the main channel which formed on the slope grew narrower and deeper as the clay content ratio increased. Vertical erosion on the bed was found to be more dominant than the lateral bank erosion. It was also understood that the erosion process and the geometry of channel network in case of cohesive bare slope have different characteristics than those of cohesionless slope.

本文对粘性泥沙的侵蚀过程进行了试验研究。为评价均匀粘性泥沙的冲刷速度，已在试验水槽中进行了基础性研究。在本研究中，我们研制了一种可移动的侵蚀试验装置，用于对天然沉积的粘性泥沙的侵蚀速率进行现场测量。我们还建立了这种测量的实验技术。为了检验该装置的有效性和实用性，在大型露天实验水槽上进行了一系列的测量。经验证，其结果与我们实验室标准试验的结果具有几乎相同的准确度。本文还研究了泥沙粘聚性对裸露坡面侵蚀过程的影响。这是本研究的第二部分。通过试验研究了人工降雨作用下由粘性泥沙组成的模型裸露边坡的地貌变化。在此之前，我们对粘性泥沙侵蚀试验技术的了解是有启发性的。粘土含量比只是在这一系列实验中需要改变的参数。结果表明，随着粘粒含量的增加，坡面上形成的主槽变窄变深。河床的垂直冲刷比侧滩冲刷更具优势。研究还表明，粘性裸露边坡的冲刷过程和河网几何形状与无粘性裸露边坡不同。