地垒构造区域内工作面矿震发生规律研究
Research on occurrence laws of shock bump in horst fault zone of working face
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摘要: 为深刻揭示和总结地垒构造区矿震规律的特殊性,以东滩煤矿1305工作面为研究对象,采用力学计算、数值模拟和微震监测相结合的方法,分析地垒构造区垂直应力二次分布,微震信号反映出矿震的影响。结果表明:工作面开采距离EF93断层距离84 m和35 m时,EF93断层和EF32断层相继发生错动,容易诱发矿震;微震监测和数值模拟叠加结果显示出震源在工作面前方和采空区后方积聚,且主要集中在顶板硬岩和应力升高区,开采距离EF93断层80 m时,断层错动诱发高能矿震,验证了力学计算结果;地垒构造区开采震动能量和频次都升高,断层活化是影响震动增强的主因;地震活性系数b值与震动能量呈负相关性,大震发生之前往往经历"小震密集-平静-大震发生"的过程。Abstract: In order to profoundly reveal the particularity of shock bump characteristics, taking Dongtan Coal Mine No. 1305 working face as the research object, the shock bump influence of the second vertical stress distribution and microseismic signal in horst fault zone were analyzed by mechanical calculation, numerical simulatio n and microseismic monitoring. The results showed that the Fault EF93 and the Fault EF32 dislocated sequentially when the coal wall was 84 m and 35 m far from the F ault EF93.Numerical simulation and microseismic monitoring showed that microseismic points always concentrated in front of the coal wall and in behind of the gob, an d mainly concentrated hard rock roof and stress-concentrated area. The high energy shock bump occurred when the coal wall was 80 m far from the Fault EF93 and pro ved the mechanical calculation. The shock energy and times all increased in horst structure zone, fault activation was the main reason of shock increased. There are so me negative correlation between shock energy and b value, so called seismic activity coefficient. It always experiences 'low energy shock concentrated-quite-high ener gy shock happened'before high energy shock bump.