近距离煤层遗留煤柱下伏巷道失稳机理研究

    Study on the instability mechanism of the roadway under the residual coal pillar in the near coal seam

    • 摘要: 为研究近距离煤层遗留煤柱下伏巷道的失稳机理及优化方案,针对当前煤炭开采中普遍存在的巷道稳定性问题,本文以神东煤炭集团的石圪台近距离1−2上煤层和1−2煤层为工程背景,采用理论分析、数值模拟等多方法综合现场实际条件分析巷道围岩失稳机理。通过构建1−2上煤层遗留煤柱载荷及底板应力传递计算模型,提出利用J2理论来判定巷道围岩的稳定性,研究得出底板应力传递规律及相应优化方案。研究结果表明:对遗留煤柱的破坏过程分析并计算得到遗留煤柱承载应力为21.44 MPa;近距离煤层遗留煤柱底板的应力以压应力主,垂直应力随底板深度的增加逐渐降低;J2随着距煤柱中心垂直距离的增加而增大。在距煤柱中心水平距离为煤柱宽度时,煤柱底板埋深越浅,偏应力J2易出现峰值;根据理论计算分析及数值模拟结果,在滞后10~20 m范围内围岩扰动较为明显,超前易在30 m处形成应力集中;随着上覆遗留煤柱宽度的增加两帮的应力差曲线逐渐呈“缓慢-急速-缓慢”降低的趋势,在上覆遗留煤柱宽度由25 m增加到30 m时,两帮的应力差值曲线降幅较大,提出上覆遗留煤柱的宽度从20 m优化为30 m,能够降低煤柱对两帮的应力非对称分布效果。研究成果可为国内矿井开发与开采提供科技支撑与理论支撑,减少遗留煤柱对巷道围岩的破坏,使巷道处于安全生产条件下,对巷道灾变的预防和治理达到可控。

       

      Abstract: In order to study the instability mechanism and optimization scheme of the roadway under the residual coal pillar in the near coal seam, in view of the common roadway stability problems in coal mining, this paper takes the 1−2 upper coal seam and 1−2 coal seam in the Shibitai of Shendong Coal Group as the engineering background, and uses theoretical analysis, numerical simulation and other methods to analyze the instability mechanism of the surrounding rock of the roadway under the actual conditions of the site. By constructing the calculation model of the load of the residual coal pillar and the stress transmission of the floor on the 1−2 upper coal seam, the J2 theory is proposed to determine the stability of the surrounding rock of the roadway, and the stress transmission law of the floor and the corresponding optimization scheme are studied. The results show that the bearing stress of the residual coal pillar is 21.44 MPa, the stress of the floor of the residual coal pillar in the close coal seam is mainly the compressive stress, and the vertical stress gradually decreases with the increase of the depth of the floor, and J2 increases with the increase of the vertical distance from the center of the coal pillar. When the horizontal distance from the center of the coal pillar is the width of the coal pillar, the shallower the buried depth of the coal pillar floor, the peak of the deviator stress J2 is likely to occur. According to the theoretical calculation and analysis and numerical simulation results, the disturbance of the surrounding rock is obvious in the lag range of 10-20 m, and the stress concentration is easy to form at 30 m in advance. With the increase of the width of the overlying coal pillar, the stress difference curves of the two gangs gradually show a decreasing trend of “slow-rapid-slow”, and when the width of the overlying coal pillar increases from 25 m to 30 m, the stress difference curves of the two gangs decreased greatly, and the width of the overlying coal pillar is optimized from 20 m to 30 m, which could reduce the stress asymmetric distribution effect of the coal pillar on the two gangs. The research results can provide scientific and theoretical support for the development and exploitation of domestic mines, reduce the damage of the residual coal pillars to the surrounding rock of the roadway, make the roadway under safe production conditions, and control the prevention and treatment of roadway disasters.

       

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