深部矿井掘进工作面煤体突出危险电位反演精细判识

Fine identification of coal and gas outbursts based on electric potential inversion method ahead of driving face of deep mine

深部煤炭开采条件下,煤与瓦斯等动力灾害更加严峻及复杂,对突出危险潜在区域进行精细判识,是监测预警深部煤与瓦斯突出灾害的基础和前提。常规预测手段无法在空间分布上对突出危险区域进行连续、精细监测。基于此,现场测试研究煤体掘进过程电位响应特征,根据双边电位反演模型提出掘进工作面前方煤体突出危险精细判识方法,并进行应用与验证。煤体掘进过程中电位信号与采动应力的变化基本一致,符合经典应力分布规律。电位信号在工作面发生大能量煤炮时处于高值水平且波动剧烈,表明电位响应能够反映煤体采动过程的受载破坏状态。构建双边电位反演成像模型,提出掘进工作面前方煤体(10 m内)突出危险判识方法。基于模糊数学统计结果确定电位反演临界值,对反演区域内的突出危险区域及危险程度进行区域划分与定量识别。结合钻孔瓦斯参数等常规指标对电位判识结果进行验证,统计表明电位反演云图中黄色危险区域对突出危险点的判识成功率为100%,红色危险区域的判识准确率为62.5%。电位反演方法能够精细判识掘进工作面前方煤体突出危险区域及危险程度,为深部煤岩动力灾害的监测与防控提供了新的研究思路和应用手段。

Under the condition of deep coal mining,dynamic disasters of coal and gas are more severe and complex.Fine identification of potential outburst areas is basic and prerequisite for monitoring and forecasting coal and gas outbursts during mining in deep mine.Conventional prediction methods cannot continuously monitor outburst zones in spatial distribution.Based on this,the characteristics of electric potential(EP)response were tested and investigated in the field during coal excavating.Based on the bilateral EP inversion model,a fine identification method was proposed,applied and verified for outbursts of coal mass ahead of the driving face.The change of EP signal and mining stress is basically similar during coal excavation,which conforms to the classic stress distribution characteristics.The EP signal is at a high level and fluctuates violently when coal blasting occurs in the driving face,indicating that the EP response reflects loading and damaging state during mining.Based on bilateral EP inversion imaging model,a method was constructed for identifying the outburst hazard zone and the degree of the coal mass(within 10 m)ahead of the driving face,while the coefficient is corrected.In this method,the critical value of EP inversion is determined by the statistical results of fuzzy mathematics,and the outburst hazard zone and hazard degree are quantitatively identified in the inversion area.The identification results from EP inversion are verified by the combination with gas parameters of boreholes.The results have shown that the success rate of identifying outburst danger points is 100%in yellow hazard zones of EP inversion cloud map,and the accuracy rate of hazard area identification is 62.5%in red hazard zones,which meets the prediction demand of safety production in coal mines.The EP inversion method can accurately identify the coal and gas outburst hazard zones ahead of driving face,which provides a new research idea and application method for the prevention and control of coal rock dynamic disasters during deep mining process.