Analysis and prevention of rock burst hazards in fold structure mining faces

YANG Yong; XIA Lei; QIANG Wei; WANG Tao; XU Guoyao

doi:10.13347/j.cnki.mkaq.20240854

Abstract：The impact risk of the mining face in the fold structure construction area is often subject to the coupling effects of mul-tiple factors.By analyzing and mutually verifying the micro-seismic monitoring and early warning information of the 7304 working face and its adjacent 7302 and 73 upper 11 working faces in the folded structure area of Baodian Coal Mine,the causes can be dis-covered in time and the impact risks can be defused.For the early warning of stress increase during the mining process of the 7304 working face,the micro-seismic monitoring data of the 7302 and 73 upper 11 working faces were used to quantitatively analyze the precurential characteristics of rock burst during the mining and tunneling of the 7304 working face,and to study the reasons for the abnormal increase in coal body stress resulting in the enhanced risk of rock burst.The research finds that various factors such as thick-layer hard roof,mining disturbance of adjacent working faces,folded structure,and mining technical conditions have different degrees of influence on the abnormal stress increase of the working face.The number,frequency and location information of micro-seismic events can reflect the action range and influence degree of different factors.Combining the planar distribution laws of micro-seismic events in the 7302 and 7304 working faces,it is found that the working face on the west wing of the seventh mining area is significantly affected by the axial area of anticline structure,and the micro-seismic events increase significantly.The maximum daily total energy is 2.48×105 J.The high-level stress in the axial region of the folded structure anticline and its interaction with mining activities are the main controlling factors leading to the early warning of stress increase in the working face.For the fold structure zone conditions,the advancement speed of the working face is maintained at 5 cuts/d(approximately 4.0 m/d),the mining intensity is relatively high,and the maximum daily average total energy reaches 1.1×105 J.According to the rotational mining layout charac-teristics of the 7304 working face and the geological structure features of the anticline,for the anticline area in the folded structure zone,the large-diameter borehole pressure relief technology of head pressure relief and two-sided pressure relief,as well as the co-ordinated control technology of strengthened support,are adopted to reduce the risk of impact.