Study On Dynamic Process Of Slope Sediment Transport With Hedgerows

Soil erosion leads to soil degradation and reduced land productivity,affecting agricultural production and food security.Hedgerows have the effect of slowing down the flow velocity of slopes and reducing the ability of water to transport sediment.Therefore,it is of great significance to study the dynamic mechanism of hedgerows retarding soil erosion on slopes.In this paper,indoor runoff scouring tests under the conditions of different slopes,different flow rates and different hedge width combinations are used to observe the slope runoff velocity,and water and sand samples,etc.,to analyze the changes of hydrodynamic parameters in the process of slope water and sediment transport.characteristics and variation characteristics of sediment transport capacity,and discuss the relationship between flow sediment transport capacity and hydrodynamic parameters.The main findings are as follows:(1)The variation characteristics of the hydrodynamic parameters of slope runoff with different hedgerows were clarifiedThe Reynolds number varies from 650 to 1213,which belongs to the transition flow.Froude number Fr>1,the flow pattern of water flow is rapid.The range of Reynolds number and drag coefficient is affected by hedge width and increases with the increase of bandwidth.The range of the Froude number is affected by both the slope and the bandwidth.The larger the bandwidth,the larger the Froude number.The drag coefficient is affected by both flow and bandwidth.The larger the flow and bandwidth,the greater the drag coefficient.Under the same flow rate,the larger the hedgerow width,the better the slowing effect on the flow velocity.The change of the shear stress is the same as the change of the resistance coefficient,indicating that the slope flow resistance has an important influence on the shear stress.The change of the stream power is similar to the change of the Reynolds number,indicating that the flow state has a great influence on the stream power.The size of the unit stream power is mainly related to the flow rate.(2)The main factors affecting the sediment transport capacity of slopes with different hedgerows were obtained.When the hedgerow width is 0.5 m,the main factors affecting the sediment transport capacity of the slope are flow rate,Reynolds number,flow velocity,and stream power;When the hedgerow width is 1 m,the main factors affecting the sediment transport capacity of the slope are: stream power,slope,drag coefficient,flow rate,and Reynolds number;When the hedgerow width is 2 m,the main factors affecting the sediment transport capacity of the slope are: flow rate,Reynolds number,drag coefficient,slope,and Manning roughness coefficient.(3)A simulation model for the sediment transport capacity of slope flow with different hedgerows is proposed.For three hedgerow widths,the sediment transport capacity can be expressed by the linear model of flow and velocity;When the hedgerow width is 0.5 m,the sediment transport capacity of the slope can be simulated by the linear models of Reynolds number and flow velocity respectively;When the hedgerow width is 1 m,the sediment transport capacity of the slope can be simulated by linear models of drag coefficient,shear stress,stream power,Reynolds number and unit stream power respectively;When the hedgerow width is 2 m,the sediment transport capacity of the slope can be simulated by the Reynolds number,drag coefficient,shear stress,and stream power linear models,respectively.