煤层底板变形与破坏规律直流电阻率CT探测

DC electrical resistivity CT survey of deformation and damage law of coal floor

从煤层开采引起底板破坏的一般规律出发,探讨了底板岩层破坏与其电阻率的响应关系。介绍了直流电阻率CT探测技术的原理与方法,按照采动底板岩层活动规律设计了探测方案,进行煤层底板破坏深度的动态直流电阻率CT探测。通过在淮北某矿1028工作面风巷中底板位置施工2个钻孔,在孔中埋置一定数量电极,形成孔间探测剖面,并根据工作面回采进度探测不同时期岩层电场变化特征,反演其电阻率值,得出煤层底板采动裂隙演化过程中的岩层电阻率响应特征和1028工作面底板破坏深度为17 m,为煤矿安全生产提供直观有效的技术参数。试验结果表明:采用直流电阻率CT探测煤层底板采动破坏带演化过程效果明显,能显示出底板在回采过程中变化破坏情况,有利于煤矿底板突水预测和突水防治措施的制订。

Based on the general laws of the floor damage caused by coal mining,the response relation between the floor rock damage and its electrical resistivity are mainly discussed.Then,the principle and method of the direct current electrical resistivity CT surveying technology are introduced.The survey plan is made according to movement characteristics of mining rock strata in floor,and the dynamic direct-current resistivity CT survey is then applied to predict the damage depth of coal floor.In the return airway of face 1028 in Huaibei Mine,two boreholes were drilled in the coal floor,with a certain number of electrodes buried in the holes,the survey profile was formed between them.With characteristics of electric fields in rock strata in different time measured according to advance of working face,and its electrical resistivity values simulated inversely,the responses of rock strata to electrical resistance during the evolution of fractures were obtained and the damage depth of coal floor in face 1028 was determined to be 17m,which provides visual and effective technical parameters for the coal mining safety.Test results show that direct current electrical resistivity CT technique can detect coal floor mining damage evolution process effectively,and illustrate the floor deformation and damage in the process of mining,which is conducive to the water-inrush forecast,prevention and control.