Study on different bottom coal thickness on floor rock-burst induced by mine tremor

Analyzing of dynamic response law of roadway floor rock-burst induced dynamic disturbance at different bottom coal thickness by using FLAC^2D.The results showed that the maximum horizontal stress increases at first and then decreases and gradually transfers toward floor depths under dynamic disturbance,the floor vertical displacement peak and plastic depth and maximum energy density all increase nonlinearly with the increase of bottom coal thickness,meanwhile the increase trend gets more and more weakly.It is easy to occur floor rock-burst for roadway induced dynamic disturbance in extremely thick coal seam,and the dynamic effect is significant.The rationality of numerical simulation analysis is verified by the analysis of mine earthquake law.The conclusions will provide reference for floor rock-burst prevention of extremely thick coal seam.