煤矿开采方式对降低冲击地压风险的研究

Research on Impact of Coal Mining Methods on Reducing Risks of Rock Burst

  • 摘要: 为研究厚煤层开采方式对冲击地压防治的影响,通过对比厚煤层分层开采和一次性放顶煤开采的覆岩结构特征及围岩应力分布状态,分析了两种开采方法对冲击地压防治的影响,并利用FLAC3D数值模拟研究了综采工作面、巷道围岩应力分布情况,分析厚煤层一次性放顶煤开采的减载减震效果。结果表明,分层开采应力峰值为30.2 MPa,厚煤层放顶煤开采法仅为25.8 MPa,放顶煤开采减弱了采空区上方围岩的应力集中,使采场周边围岩的峰值应力值降低,但峰值应力范围增大,采场周边围岩峰值应力点向采空区深处偏移;随着开采高度的增加和底煤厚度的减少,巷道和煤壁周围的应力集中迅速减小,然后趋于稳定。因此,一次性放顶煤开采可以减少巷道和煤壁周围的应力集中,从而降低冲击地压发生的风险。

     

    Abstract: In order to study the impact of thick coal seam mining methods on the prevention and control of rock burst, by comparing the characteristics of overburden rock structures and the stress distribution status of surrounding rock between thick coal seam layered mining and one-time top coal caving mining, the impact of these two mining methods on the prevention and control of rock burst is analyzed, FLAC3D numerical simulation is used to study the stress distribution situations of the fully mechanized mining face and roadway surrounding rock, and the load reduction and shock absorption effect of one-time top coal caving mining in thick coal seams is analyzed. The results show that the stress peak value of layered mining is 30.2 MPa, while the top coal caving mining method in thick coal seams is only 25.8 MPa. Top coal caving mining weakens the stress concentration of the surrounding rock above the goaf, resulting in a reduction in the peak stress value of the surrounding rock around the stope. However, the range of peak stress is increased, and the peak stress point of the surrounding rock around the stope shifts deeper into the goaf; With the increase of mining height and the decrease of bottom coal thickness, the stress concentration around the roadway and coal wall rapidly decreases and then tends to stabilize. Therefore, one-time top coal caving mining can reduce the stress concentration around the roadway and coal wall, thus to reduce the risks of rock burst occurrence.

     

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