A roadway driving technique for preventing coal and gas outbursts in deep coal mines

In deep coal mines, coal and gas outbursts are common disasters because of the high in situ stress and high gas pressure in coal seams. To eliminate the outburst risk, gob-side entry driving is proposed during the roadway excavation. To analyse the outburst risk of gob-side entry driving in a coal seam, this study employed an innovative model that incorporates a stress equilibrium equation and gas transport equation. On the basis of numerical simulations, the distribution law of displacement and stress and gas pressure in the solid coal on both sides of the gob were determined. Specifically, the gas content distribution in the solid coal along the gob, and gas emissions law during the excavation with gob-side entry driving technique were measured. Both the R index method and three-parameter index method were used for outburst risk predictions during roadway excavation with gob-side entry driving. Results showed that the surrounding rock stress, coal seam displacement, and gas pressure and gas content all were significantly reduced on both sides of the gob, and both the R index method and three-parameter index yielded values less than the outburst risk critical values. These findings verify that gob-side entry driving is an effective method for outburst-prone coal seam excavation in deep mines.