Relationship between plastic zone of roadway and coal and gas outburst hole

Abstract

The outburst hole is of great significance to study the mechanism of coal and gas outburst. Through numerical simulation, the plastic zone of coal body at the excavation head of outburst roadway is obtained and compared with the actual outburst holes. The range of the excavation head of roadway under different in-situ stress conditions is analyzed and compared. The results show that the size of plastic zone increases with the increase of the ratio of bidirectional principal stress in front of roadway excavation, and the increasing range shows an increasing trend. Different bidirectional principal stress ratios lead to different plastic zones in surrounding rock. When the ratio of bidirectional principal stress is large, the range of plastic zone is obviously different with the direction of principal stress. The plastic zone of coal at the excavation head of roadway outburst is quite consistent with the actual hole of roadway outburst in shape and position. The coal and gas outburst hole of roadway outburst is evolved and developed from the plastic zone of coal at the excavation head of roadway. The size of plastic zone of coal at the excavation head of roadway under different in-situ stress can be used as an index to analyze the strength of coal and gas outburst.

Keywords

• coal and gas outburst
• outburst hole
• plastic zone
• in-situ stress
• outburst intensity