鄂尔多斯矿区窄煤柱工作面冲击诱因及四级监测预警技术研究OA

In recent years,rock burst accidents have occurred frequently in Ordos Mining Area.Many coal mines have adjusted their mining layouts for rock burst prevention and control.To study the main controlling factors of rock burst and targeted monitoring and early warning technologies after adjusting the mining layout from wide coal pillars to narrow coal pillars,the FLAC3D numerical sim-ulation method was adopted to analyze the static load stress characteristics of the 3106 narrow coal pillar working face in Menkeqing Coal Mine and the stress adjustment law compared with the wide coal pillar mining layout;based on the distribution characteristics of high-energy micro-seismic events during the working face mining process and the seismic wave attenuation mechanism inversion method,the dynamic load sources of the 3106 narrow coal pillar working face and their attenuated disturbance effects on the sur-rounding rock of the roadway were identified.Based on the identification results of the main static and dynamic load controlling factors,a multi-scale and multi-dimensional"volume-surface-line-point"four-level monitoring and early warning technology integ-rating micro-seismic monitoring,online stress monitoring and other means is proposed,forming a complementary comprehensive early warning method.Meanwhile,an optimized monitoring layout method and early warning indicators targeting the main con-trolling factors are designed.The results show that,different from the wide coal pillar layout where coal pillars serve as the main car-rier of lateral abutment stress,the narrow coal pillar layout shifts to the solid coal on the goaf side as the primary stress carrier,with the stress influence range reaching up to 60 m;the main controlling factor of dynamic load is the sandstone main roof within 20 m of the overlying strata,which forms a type of dynamic load disturbance dominated by tensile failure after fracture;to accurately monit-or and evaluate dynamic and static loads,measures were adopted respectively:densifying underground microseismic sensors and ar-ranging stress monitoring stations within 100 m ahead of the air-return roadway.On this basis,the microseismic and stress monitor-ing indicators as well as early warning thresholds were optimized.