Study On Soil Erosion And Benefit Of Soil Conservation Of Constructing Expressway From Yichang To Changyang

This paper takes highway soil erosion as research object ,passing analysis of the related factor of soil erosion to open out soil erosion law from Yichang to Changyang situated in west region of Hubei province in the process of expressway construction.in the meantime it analyses benefit of soil conservation.These provide theories support for research of high soil erosion and soil and water conservation of similar highway for the future. The mostly conclusion is as below:(1)Superhighway soil erosion has an intimate connection with various natural factors.precipitation soil,geography, geology and vegetation etc is foundation and latent factor which produces soil erosion.but fartificial and unreasonable activity is the predominant factor which accelerates soil erosion,such as side slope's digging and throw away soil and slag at will etc.(2)rainfall erosion factor is the important reason which influences influences soil erosion, rainfall and rain intensity are the predominant factor which influences the side slope's soil erosion quantity.Rainfall is fitting with average soil erosion quantity in Frame girder plot,and there is a notable positive monolinear correlation betwween them. equations as the following:H-2 mix-sowing pattern:M=35.819R-32.74 (related coefficients r=0.9823)H-10 mix-sowing pattern:M=32.973R+217.40 (related coefficients r=0.9707)H-15 mix-sowing pattern:M=29.884R+180.05 (related coefficients r=0.9558)Rainfall and rain average intensity are fitting with average soil erosion quantity in dumping ground one and restoring ground,and there is a notable positive correlation betwween them.equations as the following:dumping ground one: M₁=0.0309RI+7.92 (589.82≥RI≥39.5, r=0.9274)restoring ground: M₂=0.0085RI-0.14 (589.82≥RI≥39.5, r=0.9220)Besides,The form characteristic of debris grain in the process of expressway construction influences its soil erosion intensity to a certain extent. Under the general circumstance,soil erosion quantity and gravel content present positive correlation.(3)In the same weather and geography and soil condition , The influence of soil erosion to three mix-seeding pattern of vegetation puts up otherness in the first year of revegetation. Soil erosion intensity to three experimental mix-seeding pattern of vegetation is that pattern of mix-seeding vegetation of grass and frutex had a best effect on reducing soil erosion and pattern of mix-seeding ofgrass ,frutex and arbor took second place and pattern of mix-seeding of grass took the last.In the experiment of vegetation selection, pattern of mix-seeding vegetation of grass and frutex,including Testuca arundinacea,Festuca rubra,Cajanus Julvus DC.,Tephrosia Candida (Roxb.) DC.and Crotalaria pallida Ait,is the best in soil conservation.Cqjanus Julvus DC, Tephrosia Candida (Roxb.) DC. and Crotalaria pallida Ait have stronger Ecological Adaptability.(4)Vegetation Fractional Cover of dumping ground adopting water and soil conservation measures is 80% after four year. Observation data shows runoff and silt content redure greatly in the forest,and its soil erosion intensity is less.(5)Suspended Net Soil Spray-Sowing Technology has better protection effect in conglomerate's slope, Shale Slopes and Limestone slope when slope's gradient is less than seventy degree. Suspended Net Soil Spray-Sowing Technology has a limit because of the in being subjected to influence of the factors, such as precipitation,slope's gradient, rock type.geography and geology etc.