State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Key Laboratory of Gas and Fire Control for Coal Mines, Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China.
Int J Environ Res Public Health. 2022 Jul 23;19(15):8949. doi: 10.3390/ijerph19158949.
Across the world, coal resource is widely utilized in industrial production. During coal mining activities, dynamic disasters may be induced, such as coal and gas outbursts, or rock burst, resulting in serious accidents or disasters. Previous studies have shown that electric potential (EP) signals can be produced during the deformation and fracture process of coal and rock mass under load. The abnormal response characteristics of EP can reveal the damage evolution and failure feather of coal mass. In this paper, the response characteristics of EP signals are analyzed with high gas testing during mining activities within deep coal seams, and the relationship between the EP response and outburst disaster hazard is studied. The results show that: (1) Under the comprehensive action of mining stress and gas effect, the coal mass was damaged and fractured, which can produce abundant EP signals, while the temporal EP response characteristics can reflect the loading state and damage evolution process inside the coal seam. (2) When coal cannon and a sudden increase of gas concentration occurred in the coal mass, the EP signal was at a high level and fluctuated violently. This can be regarded as precursory information for an outburst risk, which was verified by monitoring the results of mining stress and electromagnetic radiation (EMR). (3) Based on the unilateral inversion imaging method, EP spatial distribution law was studied and abnormal zones with high-value were identified. The zone is close to, or coincident with, the high value interval of EMR intensity and count indexes, which revealed the distribution characteristics of coal damage localization. Hence, EP monitoring results can forecast precursor information of outburst hazards temporally, and identify local zones with outburst hazard spatially. This study provides a new idea and application basis for using the EP method to monitor and prevent coal and rock dynamic disaster hazards in the field.
在全球范围内，煤炭资源被广泛应用于工业生产。在采煤活动中，可能会引发煤与瓦斯突出、冲击地压等动态灾害，导致严重的事故或灾难。先前的研究表明，在承受载荷的煤岩变形和破裂过程中会产生电位（EP）信号。EP 信号的异常响应特征可以揭示煤体的损伤演化和破坏特征。本文分析了深部煤层开采过程中的高瓦斯测试中的 EP 信号响应特征，研究了 EP 响应与突出灾害危险性的关系。结果表明：（1）在采动应力和瓦斯综合作用下，煤体受到损伤和破裂，产生丰富的 EP 信号，而 EP 时变响应特征可以反映煤层内部的受力状态和损伤演化过程；（2）当煤炮和瓦斯浓度突增时，EP 信号处于高水平且波动剧烈，可视为突出危险性的前兆信息，该结果得到了采动应力和电磁辐射（EMR）监测结果的验证；（3）基于单边反演成像方法，研究了 EP 空间分布规律，识别出高值异常区，该区域接近或与 EMR 强度和计数指标的高值区间重合，揭示了煤体损伤局部化的分布特征。因此，EP 监测结果可以在时间上预测突出灾害的前兆信息，并在空间上识别出具有突出危险的区域。该研究为利用 EP 方法监测和防治煤岩动力灾害提供了新的思路和应用基础。
