Gray Evaluation of Water Inrush Risk in Deep Mining Floor

With the increase of the mining intensity of coal resources in China, the geological conditions of minefields have become more and more complex. The mining conditions of high pressure and high stress bring great challenges to the safe mining of coal resources. To accurately evaluate the risk of water inrush from the broken floor under high pressure and high stress, a gray evaluation model coupling the work breakdown structure (WBS), the risk-based supervision (RBS) theory, ordered binary comparison quantization method, and the center-point triangular whitenization weight function was proposed in this paper. Taking the No. 2(1) coal seam of Shanxi Formation in Guhanshan minefield as an example, studying the distribution characteristics of high pressure and high stress and the water inrush mechanism from the broken floor during No. 2(1) coal seam mining and analyzing the hydrochemical characteristics of the main water inrush aquifers below the No. 2(1) coal seam floor, this paper determined five main factors, including fault fractal dimensions, aquifer pressure, water-richness, destroyed floor depth, and effective aquiclude thickness. First, the work breakdown structure (WBS), the risk-based supervision (RBS) theory, and the ordered binary comparison quantization method were used to calculate the weight vectors of each index. Then, the centerpoint triangular whitenization weight function based on the work breakdown structure (WBS), the risk-based supervision (RBS) theory, and the ordered binary comparison quantization method were constructed to evaluate the water inrush risk from the broken floor under high pressure and high stress. Finally, the risk of water inrush from the broken floor during No. 21 coal seam mining in Guhanshan minefield was predicted using the gray evolution trend, which effectively reflects the risk characteristics of water inrush from the coal seam floor under high pressure and high stress. The results show that the evaluation and prediction results are consistent with the actual situation in Guhanshan minefield, which indicates that the model is suitable for evaluating and predicting the risk of water inrush from the broken floor under high pressure and high stress.