利用双排列CP电阻率测试技术进行垂直铺塑施工质量检测研究

CONFORMATION DETECTION OF GEOMEMBRANE VERTICALLY LAID UNDERGROUND WITH TWO-ROW CP ELECTRODE ARRAY

垂直铺塑是水利、建设和环境工程等领域常用的防渗处理手段。在铺塑过程中,由不同原因造成的防渗膜布设深度不够、搭接不好以及划破等质量问题会大大降低防渗膜的防渗效能。对于这种被垂直铺设在地层中二维纤薄体分布形态的探测,是一种非常必要但又急待解决的隐蔽工程施工质量的检测难题。根据垂直布设的防渗膜对人为在地层中建立的静电场的改变,设计了双排列CP电测装置对此进行了三维电阻率探测。理论分析和野外试验表明:在实测电剖面图上低阻异常区和防渗膜的分布区域存在对应关系,异常区的尺度可以反映实际防渗膜布设的尺度;膜间搭接不好形成的裂缝显示高阻异常特征。此外还讨论了对防渗膜分布形态的反映精度及不同排列设置参数对测试结果的影响。研究表明,采用特殊设置的三维电阻率探测技术可以实现对防渗膜在地下垂直分布形态的有效探测。

The geomembrane which is laid vertically underground has been widely used in water conservancy, building groundwork and environment engineering, etc., to prevent seepage flow in the past 20 years in China. During being laid underground, the geomembrane may be not extend to the designable depth and be lacerated by sharp stone, maybe there are some blanks between the border upon plastics series. All those can make the seepage flow through the geomembrane. So it is important to inspect the conformation of those impervious geomembrane after they have been laid vertically underground. But 2D flimsy body laid vertically underground like this geomembrane is difficult to be inspected with the usual detection method. In order to meet this require, the two-row current and potential （CP） electrode array is designed to detect it on the base of electrostatic field theory. By theoretical analysis and field studies, the abnormal resistivity pattern of different conformation, the inspection precision of this method and the results different settings lead to have been made certain. The theoretical analysis and field study show the lower resistivity patterns in apparent resistivity section can reflects that the conformation of geomembrane and their size are corresponding; the blanks between the border upon plastics series can make the lower resistivity pattern larger; one tenth change of the depth of geomembrane and 0.1 m width of blank between the border upon plastics series could be detected with this method. The research result can make sure that the conformation of impervious geomembrane which is laid vertically underground can be detected clearly with the two-row CP electrode array.