回采速度对深部厚煤层正断层活化特征影响研究

Effect of mining speed on the activation characteristics of normal faults in deep thick coal seams

  • 摘要: 为了探究回采速度对正断层活化特征的影响规律,以新巨龙煤矿8302工作面为工程背景,分析正断层上盘开采扰动下的活化机制,基于数值模拟方法探究回采速度和工作面到断层的距离对断层面活化倾向性的影响特征。结果表明:正断层高位岩层为断层面活化的高风险区域,其活化倾向性指标(Ts)受断层倾角(θ)和工作面回采速度(v)的共同影响,据此可将上盘工作面回采过程中断层活化划分为准静态和活化2个阶段;随着v的增大,围岩应力峰值呈现先减小后增大的趋势,当v为3 m/d时应力峰值最小(28.12 MPa),可有效缓解围岩的应力集中;当工作面与断层距离为30 m以内时,断层面活化风险显著升高;而此回采速度下,断层面的活化倾向性最小,此时引发断层活化的距离减小至40 m,优于其他回采速度。

     

    Abstract: This study attempts to investigate the effect of mining speed on the activation characteristics of normal faults. Taking the working face 8302 of the Xinjulong Coal Mine as the engineering background, this study explores the activation mechanism under the disturbance caused by hanging wall mining of normal faults. We investigated the effect of mining speed and the distance from the working face to the fault on the activation tendency of the fault through numerical simulation. Results show that the high-level stratum of normal fault is a high-risk area for fault plane activation, and its activation tendency index Ts is influenced by fault inclination θ and mining speed v of the working face. The fault activation in the mining process of the hanging wall working face can therefore be divided into 2 stages: quasi-static and activation. With the increase of v, the peak stress of surrounding rock decreases first and then increases. When v is 3 m/d, the peak stress reaches its minimum of 28.12 MPa. This could alleviate the stress concentration of surrounding rock. When the distance between the working face and the fault is less than 30 m, the risk of fault plane activation increases significantly. However, with a mining speed of 3 m/d, the activation tendency of fault plane reaches its minimum, and the distance causing fault activation is reduced to 40 m, outperforming those with other mining speeds.

     

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