Analysis on the Influence of Coal Strength to Risk of Outburst

The lower the coal strength is, the bigger the width of stress released zone is in front of the tunneling face. Enhancement of the stress released zone width may increase the resistance of outburst and reduce the outburst hazard; in fact, most outbursts take place in the soft seam. At first, the author analyzed the relation of coal mass strength and the width of stress released zone in front of the tunneling face; then, state that the stresses make change of the gas which is in the edge of the stress released zone; to analysis the relation between coal mass strength and the quantity of gas desorption per minute. According to the research result, the coal mass strength is lower, the width of stress distressed zone is bigger, and the quantity of gas desorption per minute is bigger; but, the latter is more dominant than the earlier ones. Finally, by making use of the research result, explained the gas abnormal phenomenon that is a sign of outburst premonition, and analyzed the mechanism of outburst prevention in coal seam infusion.