RETROGRESSIVE EROSION AND LONGITUDINAL PROFILE EVOLUTION IN NONCOHESIVE MATERIAL  

作　　者：Lien-Kuang CHEN Su-Chin CHEN 

机构地区：[1]Department of Soil and Water Conservation, National Chung Hsing University, Taichung, Taiwan 402, China Dr. [2]Department of Soil and Water Conservation, National Chung Hsing University, Taichung, Taiwan 402, China Prof.

出　　处：《International Journal of Sediment Research》2006年第2期113-122,共10页国际泥沙研究（英文版）

摘　　要：Retrogressive erosion plays a significant role in soil erosion and in channel morphology evolution. Retrogressive erosion occurs and migrates when the flow conditions and/or channel bed slope change. This study investigates through a series of experiments, the migration behavior of retrogressive erosion and the longitudinal profile evolution of a channel consisting of noncohesive sediment. Experimental results indicate that retrogressive erosion can be categorized into two types, stepped and rotating. In stepped erosion a nearly parallel erosion surface migrates upstream at a constant speed. The migration speed in rotating erosion is a function of the square root of time. The experimental results reveal that the discharge does not affect the migration speed of stepped erosion. However, the migration speed of rotating erosion increases with rising discharge. The crucial difference between rotating and stepped erosion, i.e. the threshold value separating the two forms of erosion is a function of the initial channel bed lowering and critical water depth. A model of retrogressive erosion in a noncohessive channel is developed based on the experimental results.Retrogressive erosion plays a significant role in soil erosion and in channel morphology evolution. Retrogressive erosion occurs and migrates when the flow conditions and/or channel bed slope change. This study investigates through a series of experiments, the migration behavior of retrogressive erosion and the longitudinal profile evolution of a channel consisting of noncohesive sediment. Experimental results indicate that retrogressive erosion can be categorized into two types, stepped and rotating. In stepped erosion a nearly parallel erosion surface migrates upstream at a constant speed. The migration speed in rotating erosion is a function of the square root of time. The experimental results reveal that the discharge does not affect the migration speed of stepped erosion. However, the migration speed of rotating erosion increases with rising discharge. The crucial difference between rotating and stepped erosion, i.e. the threshold value separating the two forms of erosion is a function of the initial channel bed lowering and critical water depth. A model of retrogressive erosion in a noncohessive channel is developed based on the experimental results.

关 键 词：Headcuts Retrogressive erosion KNICKPOINT Stepped and rotating 

分 类 号：TV147[水利工程—水力学及河流动力学]