Study on stress distribution characteristics of mining under coal pillar in close distance coal seams
The research background was based on the mining conditions of close range coal seams in a certain mine in Inner Mongolia,the pressure distribution characteristics inside the coal pillar of the 6-1upper coal seam and the stress transfer law under the floor of the coal pillar were studied by theoretical analysis and numerical simulation.The theoretical analysis results showed that the influence dis-tance of single side advance supporting pressure of 6-1upper coal seam was 34.7 m,the superposition of pressure on both sides of coal pil-lar increases the stress concentration,the stress concentration coefficient inside the coal pillar was 7.3,the vertical depth affected by the coal pillar was 32.7 m,the horizontal range affected was 41.2 m,and the stress concentration coefficient of the 6-1 coal seam was 5.1.Numerical simulation shows that the stress concentration coefficient of the 6-1 coal seam was 4.8,it was determined that the roadway layout of 6-1 coal seam working face was 5 m away from the coal pillar.The stable bearing state of coal pillar would have significant in-fluence on the mining of 6-1 coal seam working face.In order to ensure the safe mining of the lower coal seam working face,drilling and pressure relief measures were taken for the upper coal seam coal pillar.The drilling holes were arranged in two rows and row spacing was 500 mm,hole spacing was 800 mm,and the peak value of advance supporting pressure of the return airway was reduced from 12.2 MPa to 7.8 MPa,and good results were achieved.The research results can provide theoretical basis for safe and efficient mining of close coal seam.
close distance coal seamcoal pillarnumerical simulationstress distribution characteristicsdrilling pressure relief
万方数据
维普
