Study On Risk Assessment Of Water Inrush From Coal Floor Based On FAHP-EWM Combined Weight

Water disaster is the main disaster of coal mine safety production,which is easy to cause casualties and property losses.The main coal seam S1 in a mine field of Wubu mining area is close to the underlying aquifer,and the water pressure is high,so the possibility of water inrush is great.In order to ensure the safe mining of the main coal seam,it is necessary to evaluate the risk of water inrush.Taking the early mining area of mine field as an example,combined with the influence of various main control factors of water inrush,the weight of each main control factor is calculated by different combination weighting methods.Based on the ’ vulnerability index method ’,the risk of water inrush in different areas of main coal seam floor is analyzed.The Morris method is used to analyze the global sensitivity of the water inrush vulnerability assessment model.The main results are as follows :(1)Through statistical analysis of drilling data,geological and hydrogeological data in the study area.It is determined that the Taiyuan Formation limestone aquifer is the target aquifer that affects the water inrush from the floor of the main coal seam.Take "water pressure,water-rich index,fault influence factor,fault fractal dimension value,fold fractal dimension value,effective aquiclude thickness and brittle rock thickness below the mineral pressure failure zone" as the main control factors for water inrush.Perform interpolation analysis and dimensionless processing on each factor,and generate thematic maps respectively.The subjective and objective weights of each factor are calculated by fuzzy analytic hierarchy process(FAHP)and entropy weight method(EWM).Four kinds of combination weights are calculated by addition synthesis method,range maximization method,game theory method and minimum discriminant information method.(2)According to the four combined weights,the mathematical model of vulnerability index is constructed respectively,and the information fusion technology of GIS is used to obtain the zoning of water inrush vulnerability in the early mining area.The zoning transition trends of the four evaluation results are basically the same,but there are some areas with different rating results.The Spearman rank correlation coefficient was used to optimize the evaluation results of four kinds of water inrush vulnerability.The results showed that the correlation coefficient between the vulnerability index ranking based on the minimum discriminant information method and the ’ reasonable ranking ’ was the highest.Therefore,it can be inferred that among the four vulnerability assessment results,the water inrush vulnerability assessment obtained by the combination of the minimum discriminant information method is the best.(3)The water inrush coefficient method is used to evaluate the risk of water inrush in the early mining area.The whole area is divided into water inrush danger zone.The water inrush coefficient method evaluation is compared with the water inrush vulnerability evaluation based on the minimum discriminant information method.From the variation of the two values,the risk of water inrush in the north is higher than that in the south,and there is a small area with low risk of water inrush in the middle.From the evaluation results,the regional division of vulnerability assessment is more detailed,and the evaluation results are closer to reality.The Morries method is used to analyze the global sensitivity of the water inrush vulnerability evaluation model.Combined with the calculated combined weights,it is determined that the main controlling factors that have a greater impact on the floor water inrush vulnerability evaluation model are fault influence factors and aquifer water richness index.