Method and mechanism of rock burst prevention in the steeply inclined extremely thick coal seam through stress regulation
The geological and mining conditions of the steeply inclined extremely thick coal seam differ significantly from those of general coal seams,posing a formidable challenge in rock burst prevention.A comprehensive approach integrating theoretical analysis,numerical simulation,and on-site monitoring was employed to investigate dynamic and static stress dis-tribution characteristics in the steeply inclined extremely thick coal seam.The stress regulation method for rock burst prevention was proposed,the prevention mechanism was unveiled,and these findings were applied in engineering practice.The results indicate that the steeply in-clined,extremely thick coal seam is primarily influenced by horizontal tectonic stress,which is transmitted through the roofs and floors on both sides of the working face and concentrates in the above and below zones of the roadways.While the roofs and floors of the steeply inclined extremely thick coal seam are resistant to rupture,the energies released from the fractures of these rock layers generate strong dynamic stress.The strong dynamic stress acts on the con-centrated static stress zone above and below the roadways,potentially inducing rock bursts.Accordingly,the stress regulation method was proposed,weakening the roofs and floors on both sides of the working face and the coal mass below the working face to mitigate stress transmission capacity and weaken dynamic stress disturbances.The prevention mechanism of weakening the roofs and floors was to diminish the capacity of rock masses to transmit horizon-tal stress,reducing the static stress concentration and decreasing the intensity of dynamic stress caused by rock mass fractures.Weakening the coal mass further reduces stress concen-tration below the roadways and transfers the concentrated stress to farther layers.The steeply inclined extremely thick coal seam prevention measures were optimized and designed.The criti-cal parameters of rock burst prevention measures were determined.The on-site application shows that the number of high-energy level micro-seismic events in the working face has de-creased by 143-178,and the total energy of micro-seismic events has decreased by 90％.No rock burst occurred again,and the rock burst risk has significantly decreased.The significant reduction in rock burst risk confirmed that the stress regulation method for rock burst preven-tion is effective.The research findings provide theoretical and practical support for rock burst prevention in steeply inclined extremely thick coal seams.
steeply inclined extremely thick coal seamrock burststress regulationstress transferstress concentrationmethod and mechanism of rock burst prevention
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