A fuzzy analytic hierarchy process model to assess the risk of disaster reduction due to grouting in coal mining

Water inrush greatly endangers the safety of coal mining above aquifers. To quantify and evaluate the reduction in disaster risk and ensure the safety of coal mining above aquifers, a fuzzy analytic hierarchy process model based on the fuzzy theory and hierarchy structure was established to assess the risk of water inrush with grouting reinforcement. Four first-grade indices and 14 second-grade indices were chosen to define the fuzzy evaluation system based on a case study of the Chengjiao Coal Mine, China. The grouting effect and the fault complexity were quantified by the grouting amount and fractal dimension, respectively. A weighting set was derived by the hierarchical structure for the evaluation factors. Applying the principle of fuzzy relational synthesis from multiple factors, the evaluation vector was obtained by calculating the risk degree using the fuzzy operator based on the average membership degree of each index. A comparative analysis showed a close agreement between the grouting coefficient and water inrush coefficient and the low risk obtained from the fuzzy evaluation, proving that the grouting reinforcement effectively reduced the risk of water inrushes. The successful actual project has well verified that this method is scientific and rational, which fully takes the advantages from qualitative to quantitative and of high accuracy and universal application.