煤层合并与分叉是诱发冲击地压的重要因素，合理确定煤层合并区应力分布规律与影响范围对冲击地压防治意义重大。以张双楼煤矿千米埋深煤层合并区工作面为工程背景，采用数值模拟与现场微震监测，研究了煤层合并区域采动应力演化规律与冲击危险监测预警方法。结果表明：煤层合并区超前影响范围约为100 m，而滞后影响范围约为80 m；工作面在煤层合并区回采时的峰值应力大于正常煤层，且合并区煤厚越厚，峰值应力越大。工作面接近合并区时应力梯度最大，冲击危险程度最高；进入合并区后随着底煤厚度变大，应力缓慢上升，应力变化梯度小，整体冲击危险程度较高，但冲击危险性变化不大；出合并区后一定范围内应力集中程度依然较高，具有明显的滞后性。基于微震监测系统，提出了采用冲击变形能作为煤层合并区冲击危险的预警指标，确定了预警临界值，进出合并区的监测预警结果与数值模拟以及现场矿压显现具有较强的一致性。针对合并区底煤范围大的特点，提出了合并区超深穿层底煤卸压-注水与顺层钻孔卸压相结合的防冲技术方案，实现了工作面底煤的全覆盖卸压处理，取得了显著的防冲效果，保证了工作面的安全高效回采。

The composite and bifurcation of coal seam are significant factors inducing rockburst and the stress distribution as well as the influence area is the key to the design reasonable prevention and control technologies. Taken a kilometer longwall mining in Zhangshuanglou Coal Mine as the engineering background,this paper studied the stress evolution laws and rockburst monitoring methods by numerical simulation and field microseismic system. The results show that the composite zone has an influence range of 100 m ahead the working face and the lagging area of 80 m. The peak stress is greater than that in the normal areas,the thicker the coal seam the greater the peak stress. When the working face is close to the composite zone,the stress gradient is the largest and the rockburst risk is the greatest. After entering,the stress increases slowly with the coal thickness,but the stress gradient is small,so the risk degree maintains stable as though the rockburst risk still high. After leaving the composite zone,the stress concentration is still high with obvious hysteresis. The strain energy index is proposed based on microseismic system which shows a strong consistency with the numerical simulation and the on-site underground pressure observing. Aiming to the large range of the bottom coal in the composite area,the super-deep inclined seam destress-water injection combined hole and parallel seam large-diameter-drilling are implemented in the composite area which realizes the full coverage stress relief of the coal,and takes a significant rockburst prevention effect to ensure the safety and efficient recovery of the working face.

0 引言

1 工程概况

2 煤层合并区煤体应力演化规律

   2.1 数值模型及参数

   2.2 煤厚变化区对应力的影响

3 基于冲击变形能的煤层合并区冲击危险变化规律

4 煤层合并区冲击防治和效果

   4.1 超深穿层底煤卸压-注水防冲技术

   4.2 防治效果

5 结论