Impact of double defects on seepage behavior of geomembrane lined earth-rock dams

Abstract

In this study, the unsaturated seepage theory was employed to analyze the effect of different elevations and separations of double defects in geomembrane barrier on the seepage behavior of geomembrane lined earth-rock dams. The results indicated that the separation between the defects has a significant influence on the defect-induced leakage. The increasing separation results in the increase of defect-induced leakage. When the separation reaches 3 m, the defect-induced leakage tends to decrease. The defect-induced leakage increases again when the separation is greater than 3.5 m. And defect-induced leakage increases gradually with decreasing elevation of defect, but is still in the same order of magnitude. In addition, the wetted area near the defects expands with the increasing separation between double defects. The wetted areas can be delineated by a circle, by an ellipse or by two discrete circles depending on the separation and elevation of double defects.