Study On Characteristics Of Runoff Infiltration And Erosion On The Vegetation Slope In The Loess Area Under The Condition Of Artificial Rainfall Simulation

Rainfall infiltration is one of main factors inducing slope instability. There isclose relation between sliding slope and rainfall. This paper studied the principle ofrunoff, infiltration, soil loss of slope growing Elymus dehuricus and Caraganakorshinskii through simulation rainfall in lab and compared with the principle of bareslope. Main conclusions are as follows:The location of erosion peak after rainfall is calculated by Green-Ampt modeland compared with experiment data. The erosion peak of slope growing grass andshrub is lower than those of bare slope. The lowest is the slope with Caraganakorshinskii, this indicates that plants make much water infiltration and vegetation hasanti-infiltration effect.Vegetation can decrease the time of runoff and runoff volume. Bare slope hasoptimum in time of runoff, runoff volume and runoff transferring rate. Slope growingCaragana korshinskii has the minimum. But under same rainfall intensity and samerainfall period, slope growing Caragana korshinskii has optimum, bare slope hasminimum. It shows that Caragana korshinskii is most effective in preventing rainfall.Regress analyzing shows that there is power function relation between initial losingtime of rainfall and rainfall intensity for bare slope; there is logistic relation forElymus dehuricus and for Caragana korshinskii. There exist different runoffconditions for bare slope and slope growing Elymus dehuricus and Caraganakorshinskii, so there is different regress relation of initial losing time of rainfall andrainfall intensity. This reflects different runoff principles for bare slope and slope withgrass and shrub.Conclusions are got through comparing grass slope with shrub slope in differentgrowing periods. Runoff transferring rate increases with period increasing, but Elymusdehuricus is faster than Caragana korshinskii. There was only a smaller differencebetween Elymus dehuricus and Caragana korshinskii at the initial growing period, butwith the growing period increasing and the gradual rainfall infiltration rate ofvegetation slope decreasing, the rainfall rate of Elymus dehuricus becomes smaller than that of Caragana korshinskii. Restraining runoff role for Elymus dehuricus isgreater than that of Caragana korshinskii. With growing period prolonging, such roleintense, but restraining slope sands increasing.Soil installment equipment of three kinds of experiments locate in sameenvironment. Measuring initial water content of soil before raining. The result thatwater content is minimum for Elymus dehuricus and Optimum water content is bareslope is got by measuring initial water content of soil before raining. The conclusionis: transpiration volume is optimum for Elymus dehuricus; Minimum is for bare slope.By measuring soil loss volume of slope with simulation rainfall experiment, theauthor got the following results: slope growing Elymus dehuricus has minimum soilloss volume; lope growing Caragana korshinskii stands second; bare slope hasgreatest soil loss volume. Experiment data indicates that soil loss volume is12.5timesfor bare slope than those of Elymus dehuricus. Regress analyzing showed that there islinear relationship between soil loss volume intensity and bearing raining intensity,soil loss volume intensity increase with bearing raining intensity increasing.