Study On Erosion Dynamic Process And Added Soil Erosion Of Different Underlying Surface In Shenfu Dongsheng Coalfield

Shenfu dongsheng coalfield, one of the seven largest coals in the world, is an important base of high quality coal, the energy and chemical industry with open and underground mining mainly. A lot of original landscape was destroyed in the coal mining process and different underlying surfaces such as disturbed soil, soil production road, earth-dump, high and steep slope and so on were produced in constructing coal transport lines and stripping surface and taking quarry materials, which exacerbated soil erosion and deterioration of ecological environment and had aroused great attention of community. Specialized experimental study of soil and water loss in mining areas is extremely weak, while scientific datas was urgently needed in soil conservation scheme. Therefore, in this paper, aiming at the serious problems of added soil erosion caused by shenfu dongsheng coalfield development and construction, erosion and sediment characteristic, hydrodynamic characteristic and its effect on the erosion, law of added soil erosion and protective measures of spoil body slope was analyzed under different surfaces including original soil, disturbed soil, non-hardened road and earth-dump by field scouring experiments. The study could provide a scientific basis for preventing added soil erosion and accelerating the economic development for areas, and had important scientific significance and application value. The main results were as follows:(1) Runoff rates of original soil, disturbed soil, non-hardened road and earth-dump changed stablely under different flow discharges. For certain flow discharge and slope, runoff rates increased with both slopes and flow discharges; sediment concentrations and sediment yields decreased with time but increased with both slopes and flow discharges.(2) For different flow discharges, flow shear stress, stream power and roughness coefficient on original soil, disturbed soil and non-hardened road increased gradually with time, while flow shear stress and stream power on earth-dump decreased slightly and roughness coefficient fluctuated at a certain level; for a certain slope, flow shear stress and stream power of different underlying surfaces increased, while roughness coefficient decreased with flow discharge ; for a certain flow discharge, flow shear stress and stream power of original soil increased with slope, and roughness coefficient decreased firstly and then increased for 5L/min, while on the contrary for 25L/min and increased for other flow discharges. Flow shear stress, stream power and roughness coefficient of disturbed soil and not hardened road increased with slopes.(3) Soil detachment rates on different underlying surfaces increased with flow shear stresses and stream powers and decreased with roughness coefficients. There was a linear relationship between soil detachment rate and stream power on the original soil; there was a linear relationship between soil detachment rate and both flow shear stress and stream power on the disturbed soil and not hardened road; there was a linear relationship between soil detachment rate and flow shear stress, a exponential function relationship between soil detachment rate and stream power , a power function relationship between soil detachment rate and roughness coefficient on the earth-dump.(4) Soil erosion of different underlying surfaces increased with runoff. A power function relationship existed between soil erosion and runoff of original soil, disturbed soil and not hardened road, and a linear relationship existed betwwen spoil and sand more than stone waste slag, and a exponential function relationship existed for sand less than stone waste slag; the average soil erosion of original soil was minimum and the value was 0.48kg, while erosion of spoil was maximum and the value was 22.68kg. The order of the average soil erosion of different underlying surfaces was: spoil> sand more than stone waste slag > sand less than stone waste slag > non-hardened road> disturbed soil> original soil. The soil erosion of disturbed soil,not hardened road, spoil, sand more than stone waste slag and sand less than stone waste slag increased by 4.35, 4.41, 45.27, 19.61 and 10.61 times respectively compared to original soil.(5) For a certain flow discharge, the sediment concentration and sediment yield rate on sand more than stone waste slag, sand less than stone waste slag and gangue slope carring out the measures of planting grass and fish-scale pit were significantly lower than that without any protective measures, and the values reduced volatility with time. The order of average sediment concentration and sediment yield rate of each slope after the implementation of protective measures was: no protection> planting grass> fish-scale pit. The effect of fish-scale pit was better than planting grass on reducing sediment.