FENG P F, LIU X D, ZHANG W H, et al.Study on the influence of reserved coal pillar shape on the stability of coal mine working face[J].Journal of Henan Polytechnic University(Natural Science) ,2023,42(6):19-26.

doi:10.16186/j.cnki.1673-9787.2022110019

Received:2022/11/09

Revised:2023/03/01

Published:2023/11/25

Study on the influence of reserved coal pillar shape on the stability of coal mine working face

FENG Panfei1, LIU Xudong1, ZHANG Wenhai2, PAN Pengzhi2, ZHU Hongwei1, WANG Zhaofeng2

1.State Energy Group Xinjiang Energy Co.，Ltd.，Urumqi  830000，Xinjiang，China;2.State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan  430071，Hubei，China

Abstract:In the process of coal mining，it is often necessary to reserve coal pillars as load-bearing columns to support the gravity of the upper rock mass.Due to the different width-height ratios of the reserved coal pillars on site，it has a great impact on the stability of the coal mine working face.Through uniaxial compression numerical tests conducted under different diametral-height ratios of coal rocks and their assemblages，the mechanical properties and fracture process of coal rock and its mass under different diameter-height ratios were analyzed to investigate the influence of reserved coal pillars and their mass on the stability of the working face.The results showed that：（1）As the ratio of diameter to height increased gradually，the peak strength of coal rock and its mass increased synchronously.The coal rock changed from brittle to ductile，and then from ductile to brittle，and the mass rock changed from brittle failure to ductile failure，with the ductility of the mass decreasing gradually with the continuous increase of the ratio of diameter to height.（2）With the gradual increase of the diameter to height ratio，the coal rock and its mass were mainly subjected to split failure，and the expansion direction of the crack failure is constantly changing dynamically，and the basic coal rock of the mass being broken by splitting failure.（3）The difference in peak strength between mass mass and coal rock was larger with the gradual increase of diameter to height ratio.The peak axial strain of coal rock showed no significant change with the increase of diameter to height ratio.The general trend of peak axial strain of mass mass increased with the increase of diameter to height ratio to a certain extent，and the peak axial strain of mass mass was higher when D/L=0.8.

Key words:reserved coal pillar;coal rock mass;uniaxial compression;diameter-height ratio

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