Study On The Prevention And Control Of Rock Burst In The Multi-coal Seams Stoped Working Face Under The Complex Coal Pillar

A large number of previous studies have shown that for coal seam group mining,priority should be given to mining the protective layer,and in some cases,the upper protective layer should be mined.During the actual recovery of coal seam,some unavoidable factors will affect the remaining coal pillar in the upper protective seam mining,and the remaining coal pillar will increase the impact risk of the mining of the lower seam.The 5368 working face of Evergrande coal mine is affected by the complex residual coal pillars on the upper part of the protective layer.Under this influence,the static load stress in the unrelieved area under the residual coal pillars is high,which is easy to induce rock burst.Therefore,this thesis to Evergrande coal seam group of 5368 working face under complicated legacy coal pillars as the research object,combined with the actual production situation,theoretical analysis of the working face rockburst,main control factors of coal seam is studied through numerical simulation of complex legacy under coal pillar mining face during the recovery period of the surrounding rock stress distribution and evolution characteristics,Combined with the microseismic monitoring data,the spatial-temporal evolution law of microseismic in the process of mining under the complex remaining coal pillar of coal seam group is analyzed.Finally,the monitoring and prevention technology of the impact risk of 5368 working face is put forward and put into practice in the field.The main controlling factors of rock burst in 5368 working face are analyzed theoretically,including the bursting liability of coal and rock mass,the width of coal pillar left in section,the rock structure of roof and the coal pillar left after the mining of protective bed.At the same time,the irregular unrelief area formed after the outburst protection layer is the key direction of the numerical simulation research in the later stage of 5368 working face,and it is also the key area for the prevention and control of rock burst during the mining of the working face.The numerical simulation results show that the main stress concentration area of 5368 working face is the underlying area of coal pillar area formed between the mined-out area of4311 working face and the mined-out area of 5335 working face,and the underlying area of complex remaining coal pillar between the stoping line of 5333 working face and 4311 working face without pressure relief.The analysis results of the microseismic monitoring data during the working face mining show that the large accumulation rate of high-energy mine earthquake and impact deformation energy is basically in the unrelieved area of the overlying complex residual coal pillars,which proves that the 5368 working face is greatly affected by the overlying complex residual coal pillars.Based on the analysis of the mechanism and impact force source of typical high-energy events,it can be seen that the high-energy mine earthquakes are mainly distributed in the roof area of working face.Combined with the impact characteristics of the working face under the complex remaining coal pillars in the coal seam group,the corresponding key areas for the prevention and control of rock burst were designated,and the multi-information monitoring and early warning technology system of the impact risk in the regional,local and fixed locations of the5368 working face was established.At last,the prevention and control effect of 5368 working face during mining is analyzed.It is proved that the research results of this thesis can effectively guide the safe mining of 5368 working face.At the same time,it provides a better theoretical support and technical guidance for the safe and efficient mining of the working face under similar conditions.There are 54 pictures,15 tables and 101 references in this thesis.