Study on influence of mining ground fissures on soil anti-erodibility in northern Shaanxi coal mining area

As the most prominent and typical mining damage problem in the coal mining area of northern Shaanxi in the middle reaches of the Yellow River Basin, the soil erosion effect caused by mining ground fissures can not be ignored. In order to study the influence of the development of mining ground fissures on the anti-erodibility of the surrounding soil, the mining ground fissures with widths of 0−10, 10−20 and 20−30 cm in the northern Shaanxi coal mining area were taken as the research object. The soil with a horizontal distance of less than 80 cm and a vertical depth of 40 cm was collected. Fourteen indicators widely concerned by domestic and foreign scholars for quantitatively characterizing soil erosion resistance, including soil-water stable aggregates, micro-aggregates, inorganic clays, organic clays, and physical properties, were measured. The important quantitative indexes of soil anti-erodibility in the developed area of ground fissures in northern Shaanxi were selected by the methods of analytic hierarchy process, sensitivity analysis and factor analysis, and the comprehensive index model of soil anti-erodibility in the developed area of ground fissures in northern Shaanxi was constructed. The results show that:①Comprehensive analytic hierarchy process, sensitivity analysis and factor analysis, the five indexes of >0.25 mm water-stable aggregate content, mean weight diameter, <0.001 mm fine clay content, soil reunion degree and organic matter content were selected as the key indexes for quantitative characterization of soil anti-erodibility in the mining ground fissure development area of northern Shaanxi.②Mining ground fissures will reduce the five key indicators of soil anti-erodibility in the surrounding soil, among which the content of >0.25 mm water-stable aggregates changes most obviously.③According to the important indexes of soil anti-erodibility, based on the principle of factor analysis, a comprehensive index model of soil anti-erodibility in the developed area of mining ground fissures in northern Shaanxi was established.④The mining ground fissures will reduce the comprehensive anti-erosion ability of the surrounding soil, and this effect increases with the increase of the crack width and the decrease of the horizontal distance. When the horizontal distance from the mining ground fissures exceeds 170 cm, the negative effect of the mining ground fissures on the comprehensive anti-erosion ability of the surrounding soil basically disappears, which can be used as a key area for soil erosion prevention and control in the mining-induced ground fissure development area in northern Shaanxi. The research results can provide scientific basis for accurate prevention and control of soil erosion in northern Shaanxi mining area in the middle reaches of the Yellow River.