开采扰动诱发断层应力影响范围的上行机制研究

STUDY ON UPWARD MECHANISM OF INFLUENCE RANGE OF FAULT STRESS INDUCED BY MINING DISTURBANCE

  • 摘要: 断层滑移失稳是诱发煤矿冲击地压的主要因素之一,开采扰动诱发断层面应力场动态演化特征是揭示断层滑移失稳机制的重要课题。为了探究煤层开采过程中断层面应力场特征,该文建立了考虑采动影响的断层面及其围岩应力求解力学模型,分析了断层面正应力与剪应力随工作面开采的动态演化规律,研究了不同倾角时的断层应力场和结构势能演化规律。研究结果表明:随着工作面的推进,断层面应力响应呈逐渐向断层上部扩展趋势,断层对工作面开采的影响区域最早出现在距煤层较近的断层中下部,且随着工作面的推进,该影响区域逐渐向断层顶部扩展,断层应力影响范围的上行效应越发显著;断层倾角越大,开采扰动对断层应力的影响越减小,断层面应力影响区域由下至上逐渐增大。

     

    Abstract: Fault slip instability is one of the main factors inducing coal bursts. The dynamic evolution characteristics of the stress field on the fault surface induced by mining disturbance is important to the mechanism of fault slip instability. In order to explore the stress field characteristics of the fault surface during coal mining, a mechanical model for the fault and its surrounding rock stress considering the influence of mining is established. The dynamic evolution laws of the normal stress and shear stress on the fault surface during mining are analyzed. The stress field and structural potential energy on the fault surface with different dip angles are studied. The research results indicate that: the stress on the fault surface gradually expands towards the upper of faults as the mining face advances; the influence zone on the fault starts appears in the lower part of the fault closer to the coal seam, and then gradually expands towards the fault top during the coal seam mining. Therefore, an upward trend of stress influence zone on the fault surface becomes more significant. In addition, the effect of mining disturbance on fault stress diminishes with the dip angle increase, and the area of influence zone of stress on the fault surface gradually increases from bottom to top of the fault surface.

     

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