The Mining Tremor Generation Law And Control Strategy In The Oblique Cross Fault Zone Of 3305 Working Face

In 3305 working face,there are a large number of strong quartic and above mining tremor during heading excavation.Therefore,it is of great significance to study the law of mining tremor generation and prevention countermeasures in the oblique area between 3305 working face and fault for safe mining of 3305 working face.This paper focuses on the study of 3305 working face oblique fault area mining tremor generation law,stress distribution characteristics of triangular coal pillar area under the influence of mining,3305 working face rock burst induced law,3305 working face rock burst prevention and control scheme and engineering practice,which can provide valuable reference for further revealing the internal mechanism of rock burst in fault type.Based on the theory of elastic plate and shell and the Levy method,the positive correlation between elastic strain energy and displacement of roof is revealed in this paper.At the same time,the theoretical analysis shows that with the increase of the number of empty side and the exsit of oblique area between working face and fault and,the restraining effect of high rock strata on vertical displacement of low roof and elastic strain energy accumulation will gradually weaken.Eventually,the vertical displacement and elastic strain energy of the lower roof will gradually increase.The numerical simulation shows that the inclined fault in front of the working face will lead to the obstruction of the advance abutment pressure transfering to the footwall of FD49 fault.The peak value of the advanced abutment pressure of the working face 3305 is about 60 m away from the working face,and the advanced abutment pressure begins to gradually cross the fault when the working face is about 40 m away from the fault plane.The influence range of tectonic stress of FD49 fault is about 10 m.The peak area of lateral abutment pressure is about40 m away from the air side.There is a positive correlation between the magnitude of advanced abutment pressure and the roof area of triangular coal pillar area.When the working face is 50 m away from the triangular coal pillar,the stress distribution in the triangular coal pillar area will be affected.It is suggested to implement the anti-rockburst and pressure relief measures in the area before the working face is 50 m away from the triangular coal pillar area.Further,both theoretical analysis and numerical results show that if the fault is inclined to the working face,it is necessary to plan the mining succession sequence reasonably.According to the evolution law of mining tremor energy and frequency,the sudden decrease of seismic frequency in the fourth power and above,the lower maximum energy of mining tremor energy and the equal frequency of seismic frequency with that of the previous day or several days are the precursor information of large energy seismic occurrence in triangular coal pillar area.The spatial evolution law of mining tremor shows that a large amount of energy accumulations near the fault plane along the Gui Dao roadway of 3305 working face.With the continuous advance of the working face,the advanced abutment pressure of the working face,the lateral abutment pressure of the 3303 goaf and the tectonic stress of the fault will be superimposed in this area,which may induce roof fracture,coal pillar instability or fault activation instability,thus leading to rock burst.Therefore,it is suggested to take targeted measures to reduce stress in this area.Combined with theoretical analysis,numerical simulation and conclusion of mine seismic activity law analysis,targeted rock burst prevention and control measures are formulated for the triangular area between 3305 working face and FD49 fault,including 3305 working face strike roof pre-crack and 3305 working face inclination roof pre-crack.The results of engineering practice are verified by the rules of seismic activity,drilling cuttings method and stress online method.The targeted prevention and control measures can effectively reduce the stress of the inclined area between the 3305 working face and the FD49 fault,which ensures the 3305 working face a safe mining environment.This thesis has 63 figures,10 tables and 96 references.