The subgrade slope protection projects can reduce the erosion effect of rainfall on the slope soils.In order to study the quantitative characterization method of soil and water conservation capacity of slope protection materials deeply,the rainfall erosion law of subgrade slope under different rain intensities and different three-dimensional geonet type protection was studied through indoor artificial rainfall slope erosion model test.Test measurement and calculation method were proposed.The results are drawn as follows.The dry mass of sediment loss on the slope with three-dimensional geonet protection is significantly less than that of the slope without protection under the same conditions.Geonet protection can not only reduce the amount of slope erosion,but also accelerate the process.While the soil and water conservation capacity of geonet decreases sharply with the increase of rainfall intensity.The sediment erosion rate decreases with the continuous rainfall gradually,and tends to stabilize.And fitting the erosion process by exponential function is appropriate.It is recommended that the test rainfall time of the fortified slope shouldn't be less than 70 min,and the time of the unprotected slope shouldn't be less than 100 min.The coefficient of water and soil conservation capacity decreases in a logarithmic function with the increase of rainfall intensity.When the rainfall intensity exceeds 100 mm/h,the measured value of the coefficient of water and soil conservation capacity differs greatly from the fitting value.It is suggested that the rainfall intensity should be 20～100 mm/h when measuring the coefficient of water and soil conservation capacity of materials,and 50 mm/h should be taken as the standard test rainfall intensity.The water and soil conservation capacity of three-dimensional geonet with bubble surface is better than that of ordinary three-dimensional geonet significantly,while that of three-dimensional geonet with double bubble surface is better than that with single bubble surface.The soil and water conservation ability coefficient of the three-dimensional geonet with concave and convex bubble surface is mainly distributed between 1.71 and 3.03.It is recommended that the soil and water conservation ability coefficient shouldn't be less than 1.5 when the rainfall intensity is 50 mm/h.
关键词
降雨侵蚀/边坡防护/三维土工网/模型试验/水土保持能力系数
Key words
erosion effect of rainfall/slope protection/three-dimensional geonet/model test/coefficient of soil and water conservation capacity
维普
万方数据