| With the deep mining of coal resources in China,the intensity and frequency of rock burst are gradually increasing,and the causes of rock burst are gradually becoming more and more complicated,which brings inconvenience to the safety production of coal mines.The surrounding rock of the deep roadway is subjected to high static stress for a long time,which is more sensitive to the influence of dynamic load disturbance,resulting in strong concealment of rock burst in the deep roadway and great difficulty in prevention and control.In view of the occurrence characteristics of rock burst in deep panel roadway and the problems of monitoring,prevention and control,this paper takes Gaojiapu Coal Mine of Zhengtong Coal Industry Company in Binchang Mining Area of Shaanxi Province as the engineering background.Through the processing of a large number of field measured data collected by SOS microseismic monitoring system,considering the mining connection of the first and second panel working faces,the spatial structure characteristics of the overlying strata in the main roadway are analyzed,and the influence of weak dynamic load on the surrounding rock of the main roadway during the mining process of the far field working face is studied.The mechanical tests of three different loading paths were carried out,and the influence of dynamic load disturbance on the creep of coal samples under high stress environment was obtained.Through the damage test of coal samples under cyclic dynamic load disturbance,the failure law of different strength dynamic load disturbance on different stress specimens was studied.According to the above research content,by means of theoretical analysis,the induced burst mechanism of deep roadway under far field weak dynamic load and long time high stress is revealed.According to the research results,the corresponding prevention and control measures are put forward.By using the method of large diameter drilling and coal blasting pressure relief,the pressure relief of the first panel roadway in Gaojiapu Coal Mine is carried out.By comparing the data collected by SOS microseismic monitoring system before and after pressure relief,it is found that the prevention and control measures of the main roadway have achieved good pressure relief effect,which provides a theoretical basis for preventing rock burst in the main roadway.The main conclusions are as follows :(1)By summarizing,processing and analyzing the field measured data,it is found that the interaction of long-term high stress environment and continuous far-field weak dynamic load is an important factor leading to the instability and failure of roadway surrounding rock.(2)By means of laboratory tests,it is found that the higher the stress environment is,the more sensitive the coal sample is to the weak dynamic load disturbance,and the continuous weak dynamic load disturbance will lead to the early creep failure of coal samples under high stress environment.(3)Through theoretical analysis,it is found that under the effect of continuous far-field weak dynamic load disturbance,the long-term strength of roadway surrounding rock decreases,which leads to the increase of the left neighborhood range of strength limit,and the roadway surrounding rock in high stress environment enters the accelerated creep stage in advance,eventually leading to rock burst.(4)Based on the mechanism of far-field weak dynamic load triggering deep roadway rock burst in high stress area,the pressure relief measures combined with large diameter borehole pressure relief and blasting pressure relief are put forward.By comparing the microseismic events before and after pressure relief,it is found that the pressure relief measures have achieved good pressure relief effect.Figure 57 Table 7 Reference 95... |
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