煤矿采空区及巷道的井地联合地震超前勘探

Coal-seam-ground-seismic for advance detection of goaf and roadway

废弃矿井的采空区及巷道由于位置不清楚极易造成水患危及矿工生命安全,其超前探测是煤矿一直希望解决的问题。在陕北某煤矿井下通过在煤壁中放炮,地表布设地震仪接收的方式,采集了井地联合地震数据。在对此数据进行地表高差走时补偿之后,根据速度差异,确定出了炮点前方采空区沿侧线方向上的分布边界。应用散射波成像技术,将煤层顶板滑行波在巷道边界激发的散射波能量相对增强并成像,确认此处确实存在地质不连续体(巷道)。结果表明,井下放炮,地表接收的井地联合超前探测方式,对煤层前方废弃巷道、采空区的探测具有良好的效果。

The unknown goafs and roadways of abandoned coalmines can be a serious hazard of water inrush for coalmine workers.Consequently,the advance detection of such hazard is of significance.By detonating seismic charges in underground coal seams,the seismic data can be collected using a surface survey line which is located across the surface projection of the underground shot points.This experiment was conducted at a coalmine in Shaanxi Province.After surface elevation compensation and travel time adjustments,the position of goaf boundary along the survey line was accurately determined based on the wave velocity anomaly on the seismic record.Then a scattered wave imaging technique was used to enhance the energy of the scattered waves that were generated when coal seam roof slide wave(refracted wave when the incident angle bigger than the critical angle) hit the roadway,thus the location of a geological discontinuity(roadway) was identified.This experiment results show that the coalmine-ground seismic method,employing an underground explosive charge and a surface seismic array,has the ability to detect an abandoned roadway and goaf ahead of coal mining.