Study on dynamic response characteristics of resistivity in mining failure process of working face

The mine resistivity method plays an important role in monitoring hidden danger of water hazards in coal working face. However, the abnormal response of mining failure process of coal working face will interfere with the identification of hidden danger of floor water hazards. In order to improve the interpretation precision of the mine resistivity method for monitoring hidden danger of floor water hazard in coal working face, simultaneously considering the influence of overburden failure and floor failure, a dynamic geoelectric model of the mining failure process in coal working face is established. The roof monitoring and floor monitoring are respectively carried out through three-dimensional numerical simulation and inversion imaging of mine resistivity method. The dynamic response characteristics of resistivity in the mining failure process are analyzed. The resistivity response characteristics of floor water hazard are identified and extracted. The analysis results show that the resistivity anomaly area formed in the process of mining failure moves forward with the advancing of the working face. There will be relatively low resistivity anomaly in the action range of the advance support pressure, and relatively high resistivity anomaly in the goaf area. The resistivity response at the fixed position of the working face will experience a process of first decreasing, then increasing, and then decreasing in the mining process. This process is basically consistent with the periodic stress change and failure process of the roof and floor in the mining process of the working face. The low resistance abnormal response intensity of floor water hazard is related to its position relative to the working face. When the distribution range of floor water hazard overlaps with that of goaf, the high resistance abnormal response of goaf will weaken the low resistance abnormal response of floor water hazard. When the distribution range of floor water hazard danger overlaps with the area affected by the advance support pressure, the low resistance abnormal response of the two will be superimposed together. The low resistance abnormal response can be enhanced to a certain extent. The influence of the mining damage process can be eliminated after the pure anomaly extraction of the hidden danger of floor water hazard. The pure abnormal response intensity of floor water hazards at different positions is basically the same, and their vertical influence scope is larger than that of mining damage.