| Firstly,this paper introduces the main design indexes of the 3-d geomat,and analyzes the mechanism of slope protection.In order to eliminate the uncertainty caused by the dynamic change of the underlying surface,simplify the effect of underlying surface,changing the slope from movable bed slope to fixed bed slope protection,so as to find out the 3-d geomat protection law of slope surface runoff.Based on the above research,this paper designed the fixed bed underlying surface condition of the experimental research on hydrodynamic characteristics of the overland flow on the slope with three dimensional geomat,based on the analysis of overland flow velocity,water depth,Reynolds number,Froude number,variation of drag coefficient,overland flow power,study the dynamic characteristics of water flow at different slopes(8°,14°,20°,26°,32°),with different flow rates(0.6,0.9,1.2,1.5m3/h),and different vegetation coverage(25 plant/m2,25 plan/m2),the results are as follows:1.The slope velocity increases with the increase of discharge and slope,and the velocity of flow increased significantly when the flow rate is small,while the velocity of flow is large,the growth rate is gradually reduced.The water depth increases with the increase of the flow rate,and decreases with the increase of the slope.The relationship between velocity and flow and the relationship between water depth and flow can be expressed in the form of power function;2.The Froude number increases with the slope increases,and is less affected by flow;The correlation between Reynolds number and unit discharge is positive,but it is not correlated with the slope;the flow resistance coefficient decreases with the increase of discharge rate,and the effect of flow on the drag coefficient is much larger than that of slope;3.Under the same flow rate,overland flow power increases with the increase of slope;under the same slope,the overland flow power increases with the increase of flow rate.Under different flow and different slope,stream power increases with the water flow and slope,the influence of slop power on the overland flow power is greater than the slope;4.Compared with the bare slope without vegetation,the average flow velocity of 25 vegetation coverage per square meter was reduced by 14.3%,and the average flow velocity of the slope of the plant was reduced by about50 per square meter,which was about 26.3%.In addition,the vegetation coverage has a certain reduction effect on the flow Reynolds number;Froude number,and has a certain increase effect on variation of drag coefficien.With the higher coverage rate,the phenomenon is more prominent,but with the greater flow;The phenomenon is less obvious. |
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