Study On The Relationship Between Sediment Yield And Rainfall Factors Under Natural Rainfall

The rainfall factors are the main impact factors of slope soil erosion.In the article,in order to analyze the relationship between rainfall factors and four slope types,including bare slope,vegetation slope and other two different vegetation slope forms,the field runoff plots?8m long and 1m wide?,under the circumstance of natural rainfall,had been divided into four segments,which were placed with rare-earth elements so as to observe the processes of rainfall and sediment,with it the raindrop-size distribution and slope sediment were collected.Besides,by the means of Gray Relational and Fuzzy Nearness Methods,the main rainfall factors,which exerted the impact on the sediment yield of each bare slope segment,were analyzed,and by means of Stepwise Regression Method,the relationship between sediment yield and rainfall factors.In four kinds of slopes,after analyzing the relationship between the sediment yield of which and the main rainfall factors,there came to the relevant results as follow:?1?Reached the main influencing factors on sediment yield of bare slopeAccording to the Gray Relational Analysis,the results showed that,in bare slope,the Correlation degree between whole slope,A segment and rainfall factors followed the order as:E>I₃₀>I₁₀>D₅₀>M>V_max,while in B,C and D segments,it followed the order as:E=I₃₀>I₁₀>M>D₅₀>V_max,E>I₃₀>D₅₀>V_max>M)I₁₀ and D₅₀>E>I₃₀>I₁₀>M>V_max,respectively;According to Fuzzy Nearness Analysis,the results showed that,in bare slope,the Closeness degree between sediment yield of whole slope,A,B segments and rainfall factors followed the order as:E>I₃₀>I₁₀>D₅₀>M>V_max,while in C and D segment,it followed the order as:E>I₃₀>I₁₀>M>D₅₀>V_max and D₅₀>E>I₃₀>I₁₀>M>V_max,respectively.By comparing with two methods,both of them reached the similar conclusions that the main impact factor was E?raindrop kinetic energy?,130?the maximum rainfall intensity of 30min?,with I₁₀?the maximum rainfall intensity of 10min?and D₅₀?median particle diameter of raindrop?were third and fourth,respectively.In the same bare slope,when considering the Correction degree,it was the highest between I₃₀,I₁₀,E and the sediment yield of A segment,while it was the opposite between D segment and them,showing a tendency of decreasing gradually with the sediment from A to D.The degree between D₅₀ and each segment,however,followed the opposite tendency.?2?Established the simulation equation between sediment yield of each segment and rainfall factorsIn the whole slope,the simulation equation was Y = 8.71E^0.786I₃₀^0.254?R²=0.992?,and in A,B,C and D segment,it was Y = 6.37E^0.732I₃₀^0.315?R²=0.971?,Y = 22SE^00.796I₁₀^0.485?R²=0.905?,Y=1.67E^0.772?R²=0.419?,in D segment and Y = 55.42I₁₀^1.578?R²=0.954?,respectively.?3?Analyzed the relationship between segment sediment in different underlying surface and the maximum rainfall intensity of 30minThe main source of sediment in bare slope,vegetation slope,and form two vegetation slope were A and B segment,while in form one vegetation slope,it was A segment.When the I₃₀ was lower than 0.5mm/min,in bare slope and form one vegetation slope,there was a positive correlation between the sediment yield contribution of B segment and I₃₀,while in bare slope,there was a negative correlation between the contribution of A sediment and I₃₀.When the I₃₀ was higher than 0.5mm/min,in vegetation slope and form one vegetation slope,there was positive correlation between the contribution of A segment and I₃₀.?4?Analyzed the relation between segment sediment in different underlying surface and the rainfall kinetic energyIn A,B segments of bare slope and vegetation one,A segment of form one vegetation slope,the sediment yield of which had a linear form distribution and positive correlation with rainfall kinetic energy,.In A,B segments of form two vegetation slope,it had an exponential form distribution and positive correlation with rainfall kinetic energy.?5?The simulation equation of sediment yield and rainfall factor in different slope surface is establishedVegetation slope,vegetation form and vegetation form two the yield of each slope of the E and I₃₀ and power function relationship.