Evaluation of coal and gas outburst risk based on improved AHP-GRA evaluation model

In order to improve the accuracy of risk assessment of coal and gas outburst, Gray Relational Analysis was used to calculate the correlation sequence of each influencing factor, and the gas pressure, initial velocity of gas release, mining depth, failure type and robustness coefficient of coal were selected as evaluation indexes, Analytic Hierarchy Process based on neutral reference object was proposed to evaluate the risk of coal and gas outburst in real time. The measured data of coal and gas outburst in typical mines in China were selected as samples, establishing an evaluation index model and calculating its weight value. The overall safety score of coal and gas outburst was calculated according to the pre-set evaluation index scoring rules, and the evaluation result was obtained by comparing with the set neutral reference score. The results show that the accuracy of risk assessment of coal and gas outburst is 95.7% by using improved Analytic Hierarchy Process; when the total score is higher than the neutral reference score of 50 points, it indicates that the evaluated coal seam has no coal and gas outburst risk, otherwise, it will occur, and the higher the score, the less the risk of coal and gas outburst.