Research On Inducing Mechanism And Prevevtion And Control Technology Of Rock Burst In Excavation Roadway In Mengcun Coal Mine

The Mengcun Coal Mine in Binchang Mining Area has a large coal seam depth and complex geological structure.During the construction period,rock burst has been occurred many times,which seriously affects the safety of production.In this paper,the driving roadway of Mengcun Coal Mine's central roadway and working face is taken as the research object,and the mechanism and prevention and control technology of rock burst induced by multi.roadway driving in deep structural area are studied by means of theoretical analysis,laboratory experiments,numerical simulation and on.site monitoring.According to the laboratory test and the analysis of the impact tendency,the No.4 coal seam has the strong impact tendency.Horizontal stress is the main stress field in the first mining area measured by in.situ measurement.The maximum principal stress is between 26 MPa and 38 MPa,which belongs to high and super high stress area.Through field monitoring,it is found that after excavation,the surrounding rock is divided into zones from shallow to deep,forming a structure of "rupture zone.complete zone.rupture zone".The range from shallow to deep is 0-4.3m,4.3-9m and 9-13m.Combining with the actual geological conditions,the numerical simulation is carried out by FLAC3D software.The results show that fold and fault structure will increase the supporting pressure of driving roadway.For instance,the vertical stress concentration factor reached 1.75 when the roadway was excavated to the folded crankshaft,which increased by 29.6%.The mechanism of rock burst induced by multi.roadway driving in deep structural area of Mengcun Coal Mine is pointed out.The load source of impact is divided into foundation static load and additional static load.The foundation static load is caused by the difference of deformation caused by different fracture zones of surrounding rock under multi.roadway layout.The load generally exists in the surrounding rock of roadway.The additional static load is caused by folds,faults and other structures.After superimposition,the static load level of surrounding rock of roadway increases.The relationship between the static load value and the critical value of surrounding rock impact initiation determines whether the rock burst occurs or not.According to the induced mechanism,the comprehensive prevention and control technology of "combining dredging and pressure relief" during the mine excavation is put forward,that is to optimize the tunnel layout to dredge the static load of the foundation caused by the deformation difference of the partition in the coal body,and to release the additional load of the surrounding rock of the tunnel in the structural area by the large.diameter borehole pressure relief.It is suggested that in the later stage,the roadway should be designed along the azimuth of 145.171° or the roadway with a small angle between the axis of the design roadway and the azimuth of 145.171°.The hole depth of large.diameter drilling should not be less than 7.71m,and the hole spacing should be 0.7m.The optimal arrangement of drilling is single row arrangement.The technical scheme of local drilling pressure relief for driving roadway in structural area is formulated.