地面与井下瞬变电磁法在煤矿富水区探测中的应用

Application of Ground and Underground Transient Electromagnetic Methods in Detecting Water-rich Areas in Coal Mines

为查明安源煤矿4218工作面Ⅳ-2号煤层富水情况,避免水害发生,基于瞬变电磁法及井下瞬变电磁法基本原理,在整个工作面开展了地面与井下相结合的瞬变电磁探测工作。根据瞬变电磁法对低阻异常灵敏、施工方便、勘探深度大、可准确反映含水异常范围、井下瞬变电磁法施工效率高、体积效应小、对异常位置确定更为可靠的特点,利用地面瞬变电磁从平面上圈定水害分布范围,再利用井下瞬变电磁超前探测技术对巷道前方富水情况进行精确圈定;结合地质和钻孔资料,分析地面瞬变电磁法视电阻率断面图中各地层与电性层的对应关系,推断煤层顶、底板处的相对低阻区域很可能为砂岩裂隙富水所致,由此在全区圈定出1处中等富水区和6处较弱富水区;4218工作面辅运顺槽Q6点前49 m位置处井下瞬变探测结果显示,在迎头位置顶板30°、顺层、底板45°处有4处低阻异常区,与地面解释异常对比,有3处重合,重合率较高。结果表明:地面与井下瞬变电磁法综合探测可有效提升煤层富水区探测的准确性,为矿井水害防治提供了依据。

In order to investigate the water-rich situation of coal seam IV-2 in the 4218 working face of Anyuan Coal Mine and avoid water damage,transient electromagnetic detection work combining ground and underground was carried out throughout the entire working area based on the basic principles of transient electromagnetic method and underground transient electromagnetic method.Based on the transient electromagnetic method has the characteristics of low resistance anomalies,convenient construction,large exploration depth,and the ability to accurately reflect the range of water content anomalies,and the underground transient electromagnetic method has the characteristics of high construction efficiency,small volume effect,and more reliable determination of anomaly positions.The ground transient electromagnetic method is used to delineate the distribution range of water hazards from the plane,and then the underground transient electromagnetic advanced detection technology is used to accurately delineate the water-rich situation in front of the tunnel.Based on geological and drilling data,the corresponding relationship between each layer and the electrical layer in the apparent resistivity cross-section map of ground transient electromagnetic method is analyzed.It is inferred that the relatively low resistance areas at the top and bottom of coal seam are likely to be caused by water-rich sandstone fissure.Therefore,one moderately water-rich area and six weakly water-rich areas are delineated in the entire area.The underground transient detection results at the position 49 meters before Q6 point in the auxiliary transportation trough of the 4218 working face show that there are four low resistance abnormal areas at the top plate 30°along the layer,and bottom plate 45°at the head position.Compared with the ground interpretation abnormal areas,there are three overlapping areas,the overlap rate is high.The results indicate that the comprehensive detection of ground and underground transient electromagnetic methods can effectively improve the accuracy of detecting waterrich areas in coal seams,providing a basis for mine water hazard prevention and control.