植草河床的糙率系数试验研究

Experimental Research on the Roughness of Grassed Riverbed

为分析植草河床的糙率系数取值和影响因素,采用室内物理模型和原体天然植物相结合的试验方法,选取东北地区河道滩地常见植被高羊茅,对3种不同流量、2种不同植物密度、3种不同植物高度,共21组工况进行试验分析。结果表明,天然植草河床糙率值的大致范围是0.0332~0.0641,糙率系数随着冲刷历时和流量的增大而减小,随着植物密度和植物高度的增大而增大。相同条件下,植物高度对水流的阻力作用比植物密度的阻力作用要大。

In order to analyze the value of roughness and influencing factors of grass riverbed,this paper adopts the experimental method of combining the indoor physical model with the natural plant,and selects the common vegetation festuca arundinacea in the river beach of Northeast China,and carries out an experimental analysis of three different flows,two different plant densities,three different plant heights,a total of 21 working conditions.Tests show that the approximate range of natural grass river bed roughness values is 0.0332~0.0641,grass riverbed roughness reduces with the increase in duration of erosion and flows,and increases with the increase in plant density and plant height.Under the same conditions,the resistance of plant height to water flow is more than that of plant density.