Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in t...Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in the mechanism and prevention techniques of coal bumps over the past five years in China.Based on theoretical analysis, laboratory experiment, numerical simulation and field test, the characteristics of coal bumps occurrence in China's coal mines were described, and the difference between coal bumps and rockbursts was also discussed. In addition, three categories of coal bumps induced by'material failure' were introduced, i.e. hard roof, floor strata and tectonic structures, in which the mechanism of coal bumps induced by geological structures was analyzed. This involves the bump liability and microstructure effects on bump-prone coal failure, the mechanism of coal bumps in response to fault reactivation, island face mining or hard roof failure. Next, the achievements in the monitoring and controlling methods of coal bumps were reviewed. These methods involve the incorporated prediction system of micro-seismicity and mining-induced pressure, the distributed micro-seismic monitoring system, energy absorption support system, bolts with constant resistance and large elongation,and the 'multi-stage' high-performance support. Finally, an optimal mining design is desirable for the purpose of coal bump mitigation.展开更多
This study presents a numerical investigation to assess the risk of coal bumps and produces a stress–relief technology using boreholes to mitigate risk during the extraction of an island longwall panel.Based on the g...This study presents a numerical investigation to assess the risk of coal bumps and produces a stress–relief technology using boreholes to mitigate risk during the extraction of an island longwall panel.Based on the geological condition in an island longwall panel in the Tangshan Coal Mine,Tangshan,China,a numerical FLAC3D(Fast Lagrangian Analysis of Continua in 3 Dimensions) model was established to determine and to map the zones in the panel with a high risk for coal bumps.The results of the numerical modeling show that the roof deformation starts to occur at more than 30 m ahead of the longwall face and the deformation starts to accelerate after a distance of 10 m in front of the longwall face.Large and rapid roof deformation is considered to be an important precursor of coal bump occurrence during the extraction of an island longwall panel.Based on the numerical results,a stress–relief technology using boreholes,which was employed to release abutment pressure,was investigated through numerical methods.The modeled results suggest that the peak stress concentration could be released by drilling boreholes in the zones prone to coal bumps.The effectiveness of the stress release increased with the borehole length and decreased with the borehole spacing.展开更多
基金supported by the National Key Research and Development Program (Grant No. 2016YFC0801401)National Natural Science Foundation of China (Grant No. 41502184)Beijing Natural Science Foundation (Grant No. 2164067)
文摘Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in the mechanism and prevention techniques of coal bumps over the past five years in China.Based on theoretical analysis, laboratory experiment, numerical simulation and field test, the characteristics of coal bumps occurrence in China's coal mines were described, and the difference between coal bumps and rockbursts was also discussed. In addition, three categories of coal bumps induced by'material failure' were introduced, i.e. hard roof, floor strata and tectonic structures, in which the mechanism of coal bumps induced by geological structures was analyzed. This involves the bump liability and microstructure effects on bump-prone coal failure, the mechanism of coal bumps in response to fault reactivation, island face mining or hard roof failure. Next, the achievements in the monitoring and controlling methods of coal bumps were reviewed. These methods involve the incorporated prediction system of micro-seismicity and mining-induced pressure, the distributed micro-seismic monitoring system, energy absorption support system, bolts with constant resistance and large elongation,and the 'multi-stage' high-performance support. Finally, an optimal mining design is desirable for the purpose of coal bump mitigation.
基金financially supported by the Major State Basic Research Development Program Fund of China(No.2010CB226801)State Key Laboratory for Coal Resources and Safe Mining+5 种基金China University of Mining&Technology(SKLCRSM11KFB07)China Postdoctoral Science Foundation(Nos.2011M5004482012T50161)the National Natural Science Foundation of China(No.51174213)the New Century Excellent Talents in the Ministry of Education Support Program of China(No.NCET10-0775)the Fundamental Research Funds for the Central Universities
文摘This study presents a numerical investigation to assess the risk of coal bumps and produces a stress–relief technology using boreholes to mitigate risk during the extraction of an island longwall panel.Based on the geological condition in an island longwall panel in the Tangshan Coal Mine,Tangshan,China,a numerical FLAC3D(Fast Lagrangian Analysis of Continua in 3 Dimensions) model was established to determine and to map the zones in the panel with a high risk for coal bumps.The results of the numerical modeling show that the roof deformation starts to occur at more than 30 m ahead of the longwall face and the deformation starts to accelerate after a distance of 10 m in front of the longwall face.Large and rapid roof deformation is considered to be an important precursor of coal bump occurrence during the extraction of an island longwall panel.Based on the numerical results,a stress–relief technology using boreholes,which was employed to release abutment pressure,was investigated through numerical methods.The modeled results suggest that the peak stress concentration could be released by drilling boreholes in the zones prone to coal bumps.The effectiveness of the stress release increased with the borehole length and decreased with the borehole spacing.
