锯齿形断层煤柱影响下综放工作面微震活动规律分析与研究

    Analysis and Study on the Patterns of Microseismic Activity in Fully Mechanized Top-Coal Caving Face under the Influence of Zigzag Fault Coal Pillar

    • 摘要: 近距离煤层综放工作面沿断层不规则煤柱开采时,容易形成应力集中区,对在回采过程中微震活动规律进行分析与研究,有助于掌握顶板运移规律,降低冲击地压危险程度。因此,本文以赵楼煤矿7301综放工作面为例,研究巨野矿区千米埋深综放工作面受锯齿形断层煤柱影响时微震活动规律,探讨受断层和煤柱共同影响时,不同推采速度下对微震活动及矿压显现规律的影响。通过对7301工作面微震事件空间分布和现场监测数据进行分析,主要得出以下结论根据微震主要指标的变化规律,将周期来压划分为两种类型,第一类为一次破断型,第二类为多次破断型;工作面出现较为显著的事件密集现象,出现的3个事件密集分布区域可以更好的揭示应力分布状态;运输顺槽北侧断层煤柱之中及其上方和下方出现大量微震事件,表明该处围岩处于不稳定状态,回采活动可能使断层产生一定的错动;当推采速度超过5 m/d时,微震能量相对推采速度小于5 m/d时存在明显增加,获得的合理推采速度为类似条件工作面提供了参考。

       

      Abstract: When mining along irregular coal pillars along faults in a fully mechanized top coal caving face in a short distance coal seam, it is easy to form a stress concentration area. Analyzing and studying the microseismic activity rules during mining can help to grasp the roof movement rules and reduce the risk of rock burst. Therefore, taking Zhaolou Coal Mine 7301 fully mechanized top coal caving face as an example, this paper studies the microseismic activity rule of a kilometer deep fully mechanized top coal caving face in Juye Mining Area under the influence of sawtooth shaped fault coal pillars, and discusses the impact of different mining speeds on microseismic activity and rock pressure behavior rule under the joint influence of faults and coal pillars. Based on the analysis of the spatial distribution of microseismic events and on-site monitoring data in 7301 working face, the main conclusions are as follows: According to the variation rules of the main indicators of microseismic events, the periodic weighting is divided into two types, the first type being a single break type, and the second type being a multiple break type; There is a relatively significant event density phenomenon in the working face, and the three event density distribution regions can better reveal the stress distribution state; A large number of microseismic events occurred in, above, and below the fault coal pillar on the north side of the transportation trough, indicating that the surrounding rock is in an unstable state, and mining activities may cause certain dislocation of the fault; When the pushing and mining speed exceeds 5 m/d, there is a significant increase in microseismic energy relative to the pushing and mining speed less than 5 m/d. The reasonable inferred speed obtained provides a reference for working faces under similar conditions.

       

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