The impact risk analysis and prevention practice of the coal pillar width variation area in the extra-thick coal seam

In order to analyze the impact risk of the change area of the pillar width in the extra-thick coal seam section, this paper takes the change area of the pillar width in 40103 return airway of Dafosi Coal Mine as the research object, and statistically analyzes the microseismic and geosound monitoring data before and after the change of coal pillar width, as well as the change of axial force of rockbolt and anchor cable, the influence law of the change of coal pillar width on the impact risk is analyzed, and the reason for the increase of impact risk after the change of coal pillar width is obtained, and the prevention and control measures such as weakening static load source, enhancing stability of coal pillar and improving support strength are put forward.The field monitoring results show that the targeted prevention and control measures have greatly reduced the impact risk, achieves good prevention and control effects, guarantees the safety production after the change of the width of the coal pillar on the driving face, and provides technical reference for the prevention and control of regional coal pillar impact under similar mining technology conditions.