微震异常区CT反演监测预警技术应用

Application of CT inversion monitoring and early warning technology in microseismic anomaly area

  • 摘要: 针对微震监测仅能反映微震所在区域危险性、CT反演监测不能及时反映当前工作面危险程度等问题,以山东济宁东山古城煤矿3105工作面为工程研究背景,提出了微震-应力多维信息监测预警方法,将短期的微震监测和中长期震动波CT反演监测技术相结合对工作面冲击危险区域进行判识,并结合基于中长期CT反演的大范围监测结果,利用工作面周边的微震数据对其修正,实现对工作面中长期应力演变及短期微震集聚的实时、动态监测预警。针对3105工作面2019年8月近1个月微震事件的时空分布异常情况,判断工作面前方变窄的区段煤柱区域为应力异常区域,采用CT反演技术进行危险区域划分和预警:依据CT反演结果,给出强冲击和中等冲击危险区域范围,确定3105工作面高波速冲击危险区域位于工作面材料巷和运输巷超前100~200 m区域;根据CT反演结果,按照分区管理原则,对高波速冲击危险区域采取了相应的煤层大直径钻孔、煤体爆破和深孔爆破卸压相结合的卸压解危措施。应用结果表明,利用震动波CT反演技术能准确预测两巷高波速与压力异常区对应关系,有效预测冲击危险区域,且能够区分危险等级;在高波速危险区域实施卸压措施后,有效降低了该区域微震频次及能量,微震频次及能量分别由515、12×105 J降低至338、5.98×105 J,下降了34.4%、50.2%,卸压效果明显。

     

    Abstract: In order to solve the problems that microseismic monitoring can only reflect the danger of the area where the microseisms are located, and CT inversion monitoring cannot reflect the current danger level of the working face in time, taking the 3105 working face of Dongshan Gucheng Coal Mine in Jining, Shandong as the engineering research background, a microseismic-stress multi-dimensional information monitoring and early warning method is proposed. The method combines short-term microseismic monitoring and medium and long term seismic wave CT inversion monitoring technology to identify the impact dangerous area of the working face. And the method combines the large-scale monitoring results based on medium and long term CT inversion, uses microseismic data around the working face to correct them so as to realize the real-time and dynamic monitoring and early warning of the medium and long term stress evolution of the working face and short-term microseismic accumulation. According to the abnormal situation of spatial and temporal distribution of microseismic events in August 2019 in 3105 working face for nearly one month, it is judged that the coal pillar area of the narrowing section in front of the working face is the abnormal stress area, and the CT inversion technology is adopted for dangerous area division and early warning. According to the results of CT inversion, the range of dangerous areas of strong and medium impact is given, and the high wave velocity impact dangerous area of 3105 working face is determined to be 100-200 m ahead of the material roadway and transportation roadway of the 3105 working face. According to the results of CT inversion, in accordance with the principle of zoning management, the corresponding pressure relief measures combining large diameter drilling of coal seam, coal blasting and deep hole blasting pressure relief are adopted for the high wave velocity impact dangerous area. The application results show that the seismic wave CT inversion technology can predict the corresponding relationship between high wave velocity and abnormal pressure area in two roadways accurately, predict the impact dangerous area effectively and can distinguish the danger level. After implementing pressure relief measures in dangerous areas with high wave velocity, the microseismic frequency and energy in the area are reduced effectively. The microseismic frequency and energy are reduced from 515, 12×105 J to 338, 5.98×105 J, are decreased 34.4% and 50.2% respectively. The pressure relief effect is obvious.

     

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