Impact Of Raindrop Splashing On Soil Detachment Capacity Under Red Soil Condition

In this study,red soil was the research object,the study adopted the combination of drainage scouring experiment and simulated rainfall experiment,under the combined conditions of 4 rainfall intensities,3 slopes and 5 flow rates.The thesis studied the effect of raindrop splashing on hydrodynamic parameters and soil detachment capacity;factor model of soil detachment capacity under raindrop splashing;and the fitting relationship between the soil detachment capacity with the hydrodynamic parameters and rainfall intensities under comprehensive conditions.The main results are as follows:（1）The raindrop splashing reduced the flow velocity,Froude number and unit flow power,but increased the flow depth,runoff shear force and flow power.The flow was in a jet flow pattern and transitional flow pattern.The law of hydrodynamic parameters with flow rates under the raindrop splashing was similar to that under no raindrop splashing.The combination of rainfall intensity,slope and flow rate can well predict flow velocity,runoff shear force,flow power and unit flow power.（2）Under the condition of constant slope and rainfall intensity,the soil detachment capacity increased with the increasing of discharge;Under the condition of constant scouring discharge and rainfall intensity,the soil detachment capacity increased with the increasing of slope;Under the condition of constant scouring discharge and slope,the raindrop splashing increased the soil detachment capacity.There was a good power function relationship between soil detachment capacity and rainfall intensity,slope and flow rates:D_c=0.097q^1.391S^0.805r^0.469,this model is suitable for simulating soil detachment process by flow under raining condition.（3）Under different rainfall intensities,slopes and flow rates,the soil detachment capacity increased with the increasing of runoff shear force,flow power and unit flow power.The raindrop splashing increased soil erodibility parameter K_r,reduced critical runoff shear force,critical flow power,and critical unit flow power values.The relational expression between flow power and rainfall intensity can better predict soil detachment capacity with or without raindrop splashing:D_c=0.539（ω-0.289）（1.011^I+0.391）.