ANALYSIS OF ELECTRICAL CHARACTERISTICS OF MINING DESTRUCTION ON COAL SEAM ROOF AND FLOOR WITH SIMULTANEOUS DYNAMIC MONITORING METHOD

As the depth of coal mining increases, the water hazards in mining under the deep and complicated conditions become increasingly serious. The dynamic monitoring of roof and floor failure in the coal mining process under complex conditions is of great significance to the prediction of water inrush at the mining face and the improvement of coal mining methods. Based on the parallel electrical monitoring technology, and combining the dual-mode electrode data collection method, we monitor and research the geoelectric field characteristics of the full space of coal seam roof and floor at the coal mining face simultaneously. Additionally, we obtain the synchronous response characteristics of resistivity and self-potential of the coal seam roof and floor surrounding rock before and after the mining at the first time. Research findings are as follows. The dynamic change of the cross-hole resistivity monitoring of the roof and floor can show the dynamic variation of the inter-hole resistivity with the gradual advancement of the coal mining face. It can also demonstrate the development range of the roof and floor failure zone effectively. Besides, the degree of resistivity variations caused by the apical plate collapse is greater than the degree of resistivity change caused by the bottom plate rupture. Self-potential data can reflect the roof and floor rock and fissure expansion and closure forms, and the degree of rupture. The self-potential value of the apical plate in the study area is obviously higher than the bottom plate, and the self-potential change intensity caused by the apical plate rupture is obviously greater than the bottom plate rupture. Multi-parameters are used to synchronously and dynamically monitor the roof and floor mining damage of coal seams, which has real application value to guarantee the safe mining of the mining face.