岩层变形与破坏电法测试系统研究

Study of detection system of distortion and collapsing of top rock by resistivity method in working face

利用井下钻孔电阻率法可以动态获得煤层采动过程中上覆岩层变形与破坏发育规律,根据采动进度测取不同时期岩层电场变化特征,可对岩层变形与破坏规律进行全面的分析研究。受现场测试条件所限,顶板单一钻孔所测得的数据具有全空间效应,因此,对岩层破坏定位存在一定的影响,从而降低了对覆岩破坏发育规律的认识能力。通过模型试验及现场测试效果对比,改进单孔电阻率测试方法,采用孔-巷间电阻率CT测试系统,进一步提升了原单一钻孔电法系统数据采集约束性,为电阻率分布反演及"两带"高度判定奠定基础。实际应用结果表明,孔巷电阻率CT测试图像清楚,对岩层受采动影响的破坏特征反应灵敏,提升了对岩层变形与破坏发育的解释能力。

Through borehole drilled in the top rock,the bore observing system by bore resistivity method is formed;and the distortion and collapsing characters in the top rock of the working face can be tested dynamically during digging process.According to mining velocity the changing characters of electric field in different times can be gained.And the changing law of overburden failure affected by mining can be researched comprehensively.Limited by testing condition in the spot of laneway,through single borehole in the top rock the testing data have the full space effect,the explaining result and location for rock failure is affected in different extents.Its resolution for the law of overburden failure is decreased.Through model test and practical detection,the resistivity testing method using the single borehole in the top rock is improved.The bore-laneway resistivity method is formed through laying the poles in the laneway,and the binding character of the resistivity data is enhanced compared to the single borehole system in the top rock.It provides the base for the resistivity inversion and the height judgment of the two belts.The practical researching results show that the bore-laneway resistivity CT method has sensitive reaction to structure change affected by mining;and its resistivity section is clear and dynamic.The resistivity ratio section and background detection can resolve effectively the characters of the process in the coal mining.The explaining capable of the detection achievements for the overburden failure is improved.The result is helpful to renew the practice of the overburden failure.