Coal Engineering ›› 2022, Vol. 54 ›› Issue (3): 6-11.doi: 10.11799/ce202203002

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Numerical simulation study on upward mining of pillar mined out area

  

  • Received:2021-08-04 Revised:2021-11-15 Online:2022-03-15 Published:2022-05-13

Abstract: Aiming at the problem of safe upward mining after the 5-2 coal room mining in Shenguang Coal Mine, the feasibility of upward mining of 4-2up and 4-3 coal seam and the stability of coal pillars are demonstrated by theoretical analysis. A three-dimensional numerical model was established by using 3DEC. The influence of room mining of 5-2 coal seams on the integrity and continuity of 4-2up and 4-3 coal seams was studied. The influence of upward mining of 4-2up and 4-3 coal seam on the stability of interlayer strata and coal pillar was analyzed. The results show that the ratio K of 4-2up and 4-3 coal seam is 33.07 and 23.46 respectively, which are higher than the critical value 7.5, and the ultimate bearing strength of coal pillars in the goaf of 5-2 coal seam is 7.84MPa. 4-2up and 4-3 coal seams still have certain integrity and continuity after 5-2 coal mining. The upward mining of 4-2up and 4-3 coal seam reduces the stress and displacement of interlayer rock and does not have a destructive effect on the interlayer strata and the coal pillar left in the mined-out area of 5-2 coal seam. The mine pressure behavior of interlayer strata is not obvious. Theoretical analysis and numerical simulation results show that the 4-2up and 4-3 coal seam in Shenguang Coal Mine meet the upward mining conditions.

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