Identification of mine water inrush source based on objective combinedweights-improved set pair analysis model

The occurrence of mine water hazards has a great impact on the safe mining of coal mines. Quickly and accurately identifying the water sources involved in water inrush events is one of the key means to prevent and solve mine water hazards. Based on the theory of objective combined weight and set pair analysis，aiming at the identification of mine water inrush water sources，40 water samples from four aquifers in Dongtan mining area were taken as identification samples，and six hydrochemical indexes including Na++K+，Ca2+，Mg2+，Cl-，SO2-4 and HCO-3 were selected as identification factors to build a water source identification model for mine water inrush. In addition，the model was used to identify the water source of another ten samples. The results show that the objective combination weight not only avoids the shortcoming of the subjective arbitrariness of the subjective weighting method，but also covers the shortage of strong one-sidedness from the single objective weighting method，and can reasonably assign the weight to the identification index. The weights of Ca2+ and Mg2+ are significantly higher than those of other ions，which are 0.28 and 0.25，respectively. The sum of the weights of Ca2+ and Mg2+ accounts for 53% of the overall weight，which indicates that these two indexes played major roles in the identification of water inrush sources. The 10 test samples were identified by the objective combination weight-improved set analysis model，and the accuracy rate reached 90%，indicating that the model has a certain reference value in mine water source identification. The reason for the misjudgment of the model may be that the water sampling hole is located near the fault，and the fault cuts the Jurassic red water aquifer and the Permian sandstone water aquifer，which are natural channels with certain water conductivity，resulting in water loss. There is a certain hydraulic connection and mixing with the sandstone water aquifer. It is suggested that the water samples data of various aquifers should be collected and monitored in the follow-up work，and the new water samples data should be employed to modify the model in time，so as to lay a foundation for improving the identification accuracy of the model.