水科学进展2017，Vol.28Issue(6)：849-857,9.DOI:10.14042/j.cnki.32.1309.2017.06.006
刚性植被区域床面泥沙起动特性
Sediment incipient motion on movable bed in rigid vegetation environment
摘要
Abstract
Vegetation in open channels has a significant influence on the characteristics of bed load movement. To date, studies of incipient motion of sediment in open channels with submerged vegetation have been restricted by limi-tations in statistical approaches and measuring equipment. Researchers have also neglected incipient motion of sediment in the presence of vegetation when deriving semi-empirical equations for the rates of bed load transport, and have generally considered it the same as that without vegetation, which is clearly inconsistent with, and does not re-present, the actual conditions. In this study, we therefore studied the vegetation and sandy bed in a natural river to determine the characteristics of incipient motion of sediment within rigid vegetation on a movable bed. From the spa-tially averaged velocity, we then described the incipient motion of sediment under the water-vegetation interface. We found that there were three phases of incipient motion of sediment, namely static, partially in motion, and entirely in motion. We defined the incipient motion of sediment from the conditions for the third process. We derived a semi-em-pirical equation for the sediment incipient velocity in the presence of submerged vegetation from our experimental re-sults, and found that, of the factors explored, the vegetation factor Fv had most influence on the incipient motion ve-locity of sediment with vegetation. For a given vegetation density, the average depth of the scour holes around the veg-etation elements were linearly related with the spatially averaged velocity of the flow under the water-vegetation inter-face. These results demonstrate that our method gave reasonable estimates of the spatially averaged velocity for incipi-ent motion of sediment.关键词
试验/刚性植被/泥沙/起动流速/冲刷Key words
experiment/rigid vegetation/sediment/incipient velocity/scour分类
建筑与水利引用本文复制引用
薛万云,吴时强,吴修锋,戴江玉,杨倩倩,王芳芳..刚性植被区域床面泥沙起动特性[J].水科学进展,2017,28(6):849-857,9.基金项目
国家自然科学基金资助项目( 51409165 （）
51379128)The study is financially supported by the National Natural Science Foundation of China (No. 51409165 （）
No. 51379128). （）
