Optimum selection of target strata of ground regional treatment based on analytic hierarchy process

In view of the fact that there were as many as 10 to 13 layers of limestone in Taiyuan formation in Huainan and Huaibei Coalfield, the target strata of ground regional treatment was not unique, the 18413 working face in the west 4th mining area of Pan'er coal mine was taken as an example, the optimization of the target strata was studied. The requirement of water inrush coefficient was the prerequisite for optimum selection of target strata, which determined the selection range of target strata. With C₃ ⁶ limestone as the target strata, the water inrush coefficient is less than the critical value after calculation. Therefore, it is inferred that C₃ ⁶-C₃ ¹² limestone is the potential target strata. Influencing factors such as hydrodynamic conditions, aquifer hydraulic connection, water-conducting geological structure, limestone spacing, limestone thickness and stratum injectability were the key indicators for optimum selection of target strata. However, the target strata determined by single factor analysis is incompatible with each other, which makes it difficult to achieve the optimal selection of the target strata. Therefore, the analytic hierarchy process was adopted for the optimal selection of the target strata. The optimum selection of target strata of ground regional treatment was taken as the objective layer, hydrodynamic conditions, hydraulic connection between aquifers, water-conducting geological structure, limestone spacing, limestone thickness and stratum injectability were taken as the criterion layer, and C₃ ⁶, C₃ ⁷, C₃ ⁸, C₃ ⁹, C₃ ¹⁰, C₃ ¹¹, C₃ ¹² limestone of Taiyuan formation were taken as the scheme layer, the analytic hierarchy process model was established. The judgment matrix of the target layer and the criterion layer, the criterion layer and the scheme layer were constructed, and the weight of each index of the criterion layer and the single factor score of each scheme of the scheme layer were calculated. TheCRvalues were all less than 0.10 after inspection, and judgment matrices had satisfactory consistency, meeting the consistency test. The total score of each scheme was 0.177, 0.169, 0.170, 0.214, 0.103, 0.114 and 0.053, respectively, which were calculated by the hierarchy total sort. The total score of C₃ ⁹ limestone was the largest, indicating that the optimal target stratum of ground regional treatment was C₃ ⁹ limestone. The analytic hierarchy process was applied to the study on the optimum selection of target strata of ground regional treatment, and the qualitative problem was transformed into a quantitative problem, realizing the multi-factor quantitative optimum selection of target strata, and providing a new method for optimum selection of target strata.