Experimental Study On The Relationship Between Characteristics Of Runoff Production And Sand Mixing Ratio,slope And Rain Intensity Of Sediment In Sand Covered Slope

This experiment is aimed at the problem of soil erosion in the sand-soiled land in Xiangshan area of Ningxia.The small-scale simulated rainfall physical model is used to study the actual soil in Xiangshan area,and the actual meteorological conditions,topographic features and sand-covering conditions are used as reference standards.Experiments were carried out with different rainfall intensities,different slopes and sand-covering quantities.The real-time runoff and sediment yield records in the simulated rainfall were analyzed,and the runoff and sediment yield characteristics of the sand-covered soil under different conditions were discussed.The main conclusions are as follows:(1)Under any conditions,the rate of runoff always increases rapidly at the beginning of the runoff,and then the rate of increase becomes slower or tends to be stable;the maximum value of sediment yield always occurs at the beginning of the runoff,The progress of the rain time is gradually reduced and eventually stabilizes;(2)The initial runoff time is delayed with the increase of sand mixing ratio.When other conditions are the same,the sand mixing ratio is larger and the runoff time is later.There is a good linear correlation between the two,and the rain intensity is 30mm/h.At the same time,the runoff time of all kinds of slopes(10°,20°,30°)was 38.90%,32.83%,and 73.39%,respectively.The initial runoff time increased with the slope and rain intensity;(3)Sand and gravel cover has a good inhibitory effect on runoff and sediment yield When other conditions are the same,the rate of runoff and sediment yield and the total amount of runoff and sediment yield decrease with the increase of sand mixing ratio,that is,the rate of runoff and sediment yield and total The amount of the amount is bare>25%sand ratio>50%sand ratio>75%sand ratio>full sand,75%sand mixture ratio treatment and full sand treatment on the inhibition of runoff and sediment yield Close,that is,the effect of increasing the sand and gravel content when the sand mixing ratio is increased to 75%is no longer significant;(4)When the mixing ratio of rain intensity and sand is the same,the rate and total amount of runoff and sediment yield increase with the increase of slope;When the mixing ratio of slope and sand is the same,the sediment yield and total amount of runoff increase with the increase of rain intensity.The research results have certain reference role in solving the rainwater utilization,sand-covering thickness,gravel gradation and sand-sanding slope selection.It has certain academic value for solving practical production problems and soil and water conservation theory research.