采动过程中顶板围岩水渗流自然电位响应特征  

Self-potential response characteristics to water seepage in wall rocks affected by mining

作　　者：刘静[1,2] 刘盛东[1,2] 杨胜伦[3] 王勃[1] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]安徽惠州地下灾害研究设计院,安徽合肥230088

出　　处：《煤炭学报》2013年第6期1031-1037,共7页Journal of China Coal Society

基　　金：国家自然科学基金与神华集团有限责任公司联合资助项目(U1261202);国家自然基金资助项目(51174193);"十二五"国家科技支撑计划资助项目(SQ2012BAJY3504-01)

摘　　要：阐述了2种稳态渗流模拟实验、1种采动条件下的渗流模拟实验和实际矿井突水过程中的自然电位动态监测试验情况及研究成果,以便研究矿井突水过程中的自然电位特征。均匀介质和层状非均匀介质的稳态渗流实验都证明,水头(水流前端)向电测位置的靠近会造成自然电位连续、稳步上升;故在没有采动应力影响的情况下,用自然电位的发展趋势可以反推出测区内的水流状态。在采动和非采动两种条件下的拟地层结构的渗流实验中发现,两种条件下的自然电位曲线特征明显不同;非采动条件下的自然电位曲线整体稳步上升,而采动条件下的自然电位曲线呈现大幅波动形态,采动引起的自然电位单次陡降和陡升幅度都在200 mV以上,水源充足条件下,自然电位的总体陡升幅度为600 mV左右,远远高于陡降幅度,致使自然电位最终高于背景值200 mV以上;且陡升过程往往跟随在陡降过程之后。矿井突水过程中的监测试验结论与室内实验结论具有一致性,测区突水过程前期,测线中部分电极的自然电位会连续波动,且陡降与陡升幅度都在200 mV以上;而在突水的中后期,所有测点的自然电位呈现整体大幅波动状态,最终高于初始值600 mV左右。Three kinds of experiments on water seepage were introduced in this paper, including homogeneous media physical simulation,inhomogeneous media physical simulation and heterogeneous medium simulation affected by min- ing, as long as the field detection in a coal mine where a water flood disaster happened during the geo-electrical detec- tion which lasted nearly a month. All these work were done to study the self-potential （SP） characteristics in the process of mine water inrush. Both the homogeneous and inhomogeneous media physical simulation under steady condi- tion indicates that self-potential increases continuously and steadily while water flows closer to the electrical measuring position. Consequently, flow state within the area can be deduced with the self-potential trend lines. Inhomogeneous media physical simulations with and without mining interference indicate that SP curve shapes are different between these two conditions. While SP curve arises steadily without mining interference, they fluctuate a lot under mining con- dition. Single rise or ascend SP amplitude caused by mining can reach up to 200 mV, while the increasing amplitudesummation, almost 600 mV, is bigger than the decreasing amplitude as long as the water injection is sufficient. As a re- suit, in the later stage of the experiment, SP values were 200 mV higher than those in the beginning. Moreover, SP climbs steeply following the sharp declines. The result of field monitoring of SP during the mine water inrush period is consistent to the indoor experiment conclusion ： in the earlier stage of the inrush, a few SP curves fluctuate continuous- ly, with the single rise or ascend amplitude above 200 mV ; while in the later stage all the curves fluctuates a lot and fi- nally got 600 mV higher than those of the beginning.

关 键 词：自然电位 响应特征 采动 围岩 水渗流 

分 类 号：P631.3[天文地球—地质矿产勘探]