CONDITION AND INFLUENCE FACTOR OF ROCK BURST IN HIGH GASSY COAL SEAM

Aiming at the problem of rock burst in high gassy coal seam, the occurrence conditions of rock burst are obtained by analytical analysis, the influence rule of main factors on the radius and the critical stress of the critical plastic zone are analyzed. In connection with Wulong mining practice, the effects of the coal modulus ratio, gas pore pressure, support stress, and internal friction angle on rock burst of in high gassy coal seam are analyzed in comparison. The results show that, non excavated solid coal plays a limiting role in the deformation of the roadway because of the spatial effect with excavation face nearby roadway heading face about high gassy coal seam. It reduces the danger of rock burst, the support stress of the roadway is increased in a certain distance from the rear along with the excavating face ahead. At the same time, along with the gas desorption seepage, the pore pressure of the tunnel wall is decreased, and the risk of rock and the critical stress of the high gassy coal seam tunnel decrease rapidly with the increase of the modulus ratio λ=E and the pore pressure, and they increase with the increase of the support stress, the radius of the critical plastic zone increases with the increase of the internal friction angle, the relationship between the critical stress and the internal friction angle is not monotone, there exists a minimum value, when the internal friction angle is less than the minimum value, the critical stress decreases with the increase of the internal friction angle; when the internal friction angle is larger, the results are opposite.