基于地震槽波与纵波的采煤工作面高应力区探测技术

    High stress zone detection technology of coal face based on seismic slot wave and P-wave

    • 摘要: 随着煤矿生产区域向深部转移,开采深度持续增加,开采条件趋于复杂,冲击地压灾害趋于严重,迫切需要能够准确探测采煤工作面高应力区空间分布的探测手段。通过单轴压缩试验,研究了煤岩样在单轴压缩下的地震纵波速度变化,发现在单轴压缩下的弹性阶段,煤岩样轴向地震纵波速度随着应力增加而升高,直至煤岩块遭受破坏,波速迅速下降,地震波速与应力的响应曲线表明在煤岩样弹性阶段地震纵波与应力呈正相关关系;同时也尝试研究了单轴压缩条件下地震槽波速度与应力的响应曲线特征,发现地震槽波与应力呈正相关关系,也可用于采煤工作面高应力区探查;拟将地震槽波与纵波联合用于探测应力集中区。选取了地质条件简单的采煤工作面开展高应力探测试验,在试验数据中提取了纵波的初至速度和槽波特定频率下的速度,经过CT层析成像后形成波速等值线图,然后结合巷道相关资料对比分析,分别圈出各自的高速区,并按照地震波速与应力的正相关关系,将高速区解释为高应力区,最终把两者的重叠区域作为工作面冲击地压高风险区。经钻孔和回采验证:在应力重叠区施工钻孔时煤粉量明显偏大,易缩孔;回采通过应力重叠区时,巷道变形相对较大,“煤炮”时有发生。联合勘探试验表明槽波可用来探测采煤工作面的高应力区,与纵波相结合能够克服单一物探手段的局限性,更准确地探测冲击地压矿井采煤工作面的高应力区。

       

      Abstract: As the coal mining area shifts towards deeper depths, mining depth continues to increase, mining conditions become more complex, and ground pressure disasters become increasingly severe. There is an urgent need for accurate detection methods capable of spatially detecting high-stress areas in coal mining faces. Through uniaxial compression test, the variation of seismic longitudinal wave velocity of coal and rock samples under uniaxial compression was studied. It was found that during the elastic stage of uniaxial compression, the axial seismic longitudinal wave velocity of coal and rock samples increased with increasing stress until the coal and rock blocks were damaged, and the wave velocity rapidly decreased. The response curve of seismic wave velocity to stress showed that there was a positive correlation between seismic longitudinal wave and stress during the elastic stage of coal and rock samples; at the same time, the response curve characteristics of seismic slot wave velocity and stress under uniaxial compression conditions were also studied, and it was found that there was a positive correlation between seismic slot wave and stress, which could also be used for exploring high-stress areas in coal mining working face. It is proposed to use seismic slot wave and longitudinal wave together to detect stress concentration areas. Simple geological conditions of coal mining working face were selected for high-stress detection experiments, and the initial arrival speed of longitudinal wave and the speed at a specific frequency of slot wave were extracted from the test data. After CT tomography imaging, a contour map of wave velocity was formed. Then, combined with the relevant information of roadway, the high-speed area was circled respectively, and according to the positive correlation between seismic wave velocity and stress, the high-speed area was interpreted as a high-stress area. Finally, the overlapping area of the two was taken as a high-risk area of impact ground pressure in the working face. Through drilling and mining verification: when drilling in the stress overlap area, the amount of coal powder was obviously larger, easy to shrink holes; when mining passed through the stress overlap area, the deformation of roadway was relatively large, and “coal cannon” occasionally occurred. The joint exploration test shows that trough waves can be used to detect high-stress areas in coal mining working face, and combining longitudinal waves can overcome the limitations of single geophysical exploration means and more accurately detect high-stress areas in impact ground pressure mines.

       

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