Experimental Study of the Bulge Deformation of Anti-Seepage Geomembranes over Non-Fine Concrete

This study investigates the bulge deformation mechanics of geomembranes that are interacting with non-fine concrete cushions. We conducted 3D scanning of non-fine concrete specimens and further analyzed the depth-to-width ratios for non-fine concrete specimen surfaces. Then, stress distribution characteristics between the geomembrane and the non-fine concrete contact surface under diverse normal pressures were measured using a thin-film pressure transducer. It was observed that the contact surface between the geomembrane and the non-fine concrete expanded when the normal pressure increased, and the stress growth rate decreased as the area of the high-stress regions increased. Combining the relationship that was formed by the sags of the non-fine concrete surface soil with the stress distribution on the contact surface, the maximum bulge depth and the highest strain were determined following the formation of geomembrane bulge under various normal pressures. Moreover, ultrahigh strain, but not fracture, developed on the geomembrane during the experiment. Based on air bulking tests, it was demonstrated that the geomembrane had enormously high yield strength, which plays a critical role in the improvement of both the safety and the reliability of geomembranes that are mounted on non-fine concrete cushions.