Tensile failure mechanism and stress-strain behavior of scratched HDPE geomembranes

In the application of geomembranes (GMBs) for anti-seepage purposes, damage and defects are almost inevitable and can lead to premature failure during their service life. This study conducted a series of indoor tensile tests on defective GMBs to evaluate the effects of various defect types, locations, and geometric characteristics on their failure behavior. The results were validated through orthogonal tests to determine the influence of defect quantity and combination patterns on GMB performance. Furthermore, the performance at different stages was assessed under the condition of varying scratch geometric characteristics. The findings indicate that scratches pose a greater threat to GMB performance compared to other defect types. At the same angle, variations in scratch position have a negligible effect on mechanical properties. Among scratch geometric characteristics, length and angle are the primary factors affecting performance. For practical engineering applications, the allowable tensile stress range for scratched GMBs should be maintained between 2.97 and 3.50 MPa, while the allowable tensile strain range should be confined to 1.78–3.30 %. The evaluation and prediction of each stage of scratched GMBs can provide references for design engineers and the repair of scratched GMBs.