关键词: 土工膜, 缺陷探测, 电极位置, 探测间距, 数值模拟

Abstract: In the light of the similarity of governing equation and boundary condition between electric field and seepage field, the potential distribution on the surface of defective impermeable geomembrane was simulated via finite element approach. The anomaly potential distributions in the vicinity of defect were obtained to determine the location of defect. In addition, sensitivity analysis of the buried position of electrode, excitation voltage, and dipole spacing were taken into account. The computed results demonstrate that the defect in the geomembrane can be accurately located by using pole-dipole electrical survey methods. The detection of defect is more effective for a closer distance between the defect and the electrode; the detection efficiency can be increased when the detective line is along the center line of defect. The results also show that the dipole spacing of 5%-10% of the length of survey line is appropriate for detecting the defect in geomembrane. The calculated results are of theoretical guiding significance for the application of pole-dipole electrical survey methods to the detection of geomembrane defect.

Key words: geomembrane, defect detection, location of electrode, detection distance, numerical simulation