Numerical simulation and control of a rockburst induced by main roof fracture in a deep coal seam

Abstract

ABSTRACT In view of the engineering problem whereby the main roof fracture of deep coal seam still induces frequent rockburst after soft direct roof buffering, a UDEC numerical model was established based on the actual geological conditions of a mine, and the influences of the length of hanging roof and periodic weighting step on the stress in front of coal wall were discussed. The dangerous area at most risk of rockburst in the working face was monitored by using core-drilling, the risk of a rockburst was predicted by classification, and countermeasures were taken against all levels of rockburst. The results show that the longer the hanging roof length, the higher the stress in front of coal body; However, when the coal body changes from an elastic state of stress to a plastic state of stress, the stress will suddenly decrease, the range of variation of stress under static load is larger than that under dynamic load, which indicates that shock wave attenuates the stress in front of the coal body. The larger the periodic weighting step distance, the higher the stress in front of coal body, and the greater the increase of stress. However, compared with the attenuation effect of dynamic load, when increasing the hanging roof distance, the attenuation effect of dynamic load under the condition of increasing the periodic weighting step distance is greater. Dynamic load or static load will increase the stress in front of coal wall, which will lead to a rockburst. The techniques of large-diameter borehole pressure relief, coal seam water injection, and pressure relief blasting can be used to control the high-stress area monitored, ensuring the safe mining of the working face, so that coal resources can be extracted efficiently, and the rate of utilization of coal resources can be improved.