Analysis of the location of a lower coal seam roadway under multiple stress disturbances in a close coal seam.

Abstract

Multiple mining in the near coal seam leads to the complexity of stress distribution and damage of surrounding rock in the pre-excavated lower coal seam roadway, so the location of the lower coal seam roadway is extremely important. With the engineering background of multiple mining of coal seam in Fenxi coal mine, similar simulation test, numerical simulation and theoretical mechanical modeling are used to study and analyze the stress distribution law and damage characteristics of the surrounding rock in the coal roadway under the multiple stress disturbances in the near distance. The study shows that: in the multiple mining of close coal seams, after the upper working face, neighboring and adjacent working faces are mined, the damage zone of the floor in the roadway of the lower coal seam pre-mining face is the interface of the damage of the floor surrounded by rock caused by the advancing direction of the working face and the concentration of the lateral coal pillar; the deep part of the roof of the roadway of the lower coal seam pre-mining face is in the zone of the multi-stress disturbances and damages, and the shallow part of the roof is in the zone of the single stress disturbance and damages; and the deeper part of the roof of the lower coal seam pre-mining face is in the zone of the multiple-stress disturbance and damages, the deeper part is in the zone of the single stress disturbance and damages. Through the establishment of multiple mining floor damage mechanics model in the close coal seam, the multiple support stress distribution and the extension range of multiple damages are analyzed, so as to guide the reasonable arrangement of the roadway and the control of the perimeter rock support in the close lower coal seam.