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近距离陷落柱对工作面推进的影响研究

Study on influence of close collapse pillar on advancement of working face

  • 摘要: 针对工作面经过近距离陷落柱期间来压异常、支架压力变化频繁等现象,以某矿63310工作面内的635号和637号陷落柱为工程背景,采用理论分析、数值模拟和现场监测相结合的研究方法,研究了单一陷落柱周边的应力分布特征、陷落柱周边塑性扩展区域和陷落柱柱体之间的应力分布状态,分析了近距离陷落柱对工作面推进的影响规律。建立了圆形陷落柱围岩力学模型,确定了单一陷落柱周边围岩塑性扩展区域的半径。结合近距离陷落柱之间的位置关系和单个陷落柱的塑性扩展区域的大小,提出了判断陷落柱之间应力状态的方法ΔL,确定了当ΔL<0时,陷落柱的塑性扩展区域交叉重叠,陷落柱之间处于应力降低状态;当ΔL=0时,陷落柱塑性扩展区域的边界刚好接触,陷落柱之间处于由塑性应力降低向弹性应力升高过渡的临界状态;当ΔL>0时,陷落柱之间处于弹性应力升高状态或原岩应力状态;根据63310工作面2个陷落柱具体地质条件,量化了陷落柱之间的ΔL大小,确定了陷落柱之间处于应力升高状态。数值模拟分析了陷落柱周边的塑性扩展区域的大小和柱体之间的应力分布状态,确定了工作面距离637号和635号陷落柱的安全距离分别为30 m和50 m,数值模拟结果与理论分析提出的判断方法ΔL相互验证。该研究成果可为类似条件下的工作面过陷落柱提供借鉴和参考。

     

    Abstract: In view of the phenomenon that the working face passes through the close collapse pillar, the pressure changes frequently, the paper employed the No.635 and No.637 collapse pillars in the No.63310 working face of a mine as the engineering background, using a combination of theoretical analysis, numerical simulation and on-site monitoring ,the stress distribution characteristics around the single collapse pillar, the plastic extension area around the collapse pillar and the stress distribution state between the collapse pillars were studied. The influence law of the close collapse pillar on the advancement of the working face was analyzed. The surrounding rock mechanics model of the circular collapse pillar was established, and the radius of the plastic expansion zone of the surrounding rock around the single collapse pillar was determined. Combining the positional relationship between the close collapse pillars and the plastic expansion area of the single collapse pillar, the method ΔL for judging the stress state between the collapse pillars was proposed. It is determined that when ΔL0, the collapsed pillar is in an elastic stress state or an original rock stress state; according to the specific geological conditions of the two collapse pillars of the 63310 working face, the ΔL size between the collapse pillars is quantified, and the stress rise between the collapse pillars is determined. The numerical simulation shows the size of the plastic expansion zone around the collapse pillar and the stress distribution state between the cylinders. The safety distances of the working face distances No.637 and No.635 were determined to be 30 m and 50 m, respectively. The judgment method ΔL proposed by the theoretical analysis mutually authenticated. The research results can provide reference for the working face over the collapse pillars under similar conditions.

     

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