Hydrodynamic characteristics of soil erosion on depositslope under engineering measures
Niu Yaobin, Gao Zhaoliang, Liu Zizhuang, Zhang Shaojia
1. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100, Yangling, Shaanxi, China;2. University of Chinese Academy of Sciences, 100049, Beijing, China;3. Institute of Soil and Water Conservation, Northwest A&F University,712100, Yangling, Shaanxi, China;4. College of Resource Environmental Sciences, Northwest A&F University, 712100, Yangling, Shaanxi, China
Abstract：Engineering deposit formed during the process of engineering construction has unique soil composition and complex underlying surface. This sort of deposit is characterized by weak anti-scourabilty due to loose texture, which may cause severe soil erosion. Hydrodynamic parameters and their relationships with runoff in steep engineering slope show different characteristics in response to hydrodynamic conditions. Most physically based soil erosion prediction models established so far are onthe basis of hydraulic characteristics. A detailed study of the hydrodynamic characteristics is the precondition and foundation to understand erosion processes on engineering deposit. Study on the characteristics of hydrodynamic parameters of soil erosion on deposit slope under different engineering measures would be helpful to provide an optional theoretical reference for selection of suitable measures.Moreover, in order to explore the optimal hydrodynamic parameters for describing the process of soilerosion under different engineering measures (fish-scale pit and level terrace), a field scouring-erosion experiment was conducted on steep slopes under three slope gradients of 24°, 28° and 32°. Runoff kinetic energy, flow shear stress and runoff power were selected as main parameters to analyze the hydraulic process of rill flow stripping surface soil particles. Results showed that on slopes under measures of fish-scale pit and level terrace, soil erosion amount was reduced because of higher soil anti-erodibility. Soil detachment rate showed a good linear relationship with both flow shear stress and streampower, while it had a logarithmic relationship with flow kinetic energy. The rill erodibility of engineeringdeposit under the condition of fish鄄scale pit was calculated to be 1为1*10-3s/m and 2.6 *10-3s2/m2,and the rill erodibility of engineering deposit under the condition of level terrace was calculated to be 5*10 -4s/m and 1.7 *10-3s2/m2. Under the same slope of engineering deposit, protection of level terracewas better than that of fish-scale pit, but the effects of these two measures had limitation in time.
2015, Vol. 13 
