The Feature of Sediment Yield and Hydrodynamics of Different Underlying Surfaces in the Construction of the Shenfu-dongsheng Coal Field
|School||Graduate School,Chinese Academy of Sciences|
|Course||Soil and Water Conservation and Desertification Combating|
|Keywords||shengfu-dongsheng coal field different underlying surface runoff sediment yield hydrodynamics|
Amount of the disturbed lands, unpaved roads, abandon soil, slag bodies and coal refuses in the development of the coal mine were the main material sources to the loss of soil and water. The shenfudongsheng coalfield was the national key surveillance area of the soil and water erosion, because of its fragile ecological environment and severe climate condition. This paper researched runoff, sediment yield and hydrodynamics of the original lands, disturbed lands, unpaved roads and abandon soil and slag bodies, using the rainfall simulation experiment, in the shenfudongsheng coalfield, as to seek the rules and the models of the soil and water erosion, and provided some basic advises for the control measures. Main conclusions showed as follow:(1)there was a linear relationship between runoff rate and rainfall intensity. Runoff rate of different underlying surface presented trend of increases first then fluctuation stable. The orders of the runoff were: unpaved roads > abandon soil > slag bodies of more sand > slag bodies of less sand > original lands > disturbed lands > coal refuse.(2)Soil moisture content in the 1m soil layer of the original lands, disturbed lands and unpaved roads increased with the depth increase before rainfall, which decreased with the depth increase after rainfall. There was no different in the soil moisture content of below 40cm soil layer before and after rainfall, the order of which of 0-40cm soil layer were: disturbed lands > original lands > unpaved roads.(3)Sediment concentration and sand transport rate of runoff of the different underlying surfaces increased with the rainfall intensity increase, both of which had a power function relationship with rainfall intensity. The sediment concentration of the original lands, disturbed lands and unpaved roads all increased gradually with the rainfall time under the condition of small gradient and little rainfall intensity, and presented a trend of increase first and decrease after under the condition of big gradient and heave rainfall intensity. The sediment concentration of the abandon soil and slag bodies presented a tend of decrease, and became very large at some time, in which it occurred small landslides and debris flow, and then decreased rapidly. The order of sediment yield of different underlying surfaces in actual situation were: abandon soil > slag bodies of more sand > slag bodies of less sand > unpaved roads > disturbed lands > original lands > coal refuse.(4)Flow rate, Reynolds number, flow depth, stream shear force and stream power of different underlying surfaces increased with rainfall intensity increase, all of which had linear or power relationships with the rainfall intensity.(5)Soil erosion rate had linear or power relationships with rainfall intensity, flow rate, flow depth, stream shear force and stream power, which of abandon soil and slag bodies of sand more was affected less by flow rate.(6)The dispose of planting grass and digging hollow of fish scale both had the affect of decreasing runoff, also can fasten the slope surface and prevent the small landslides happens.