Experimental Study of Static Shear Strength of Geomembrane/Geotextile Interface Under High Shear Rate

Abstract

Due to its perfect anti-seepage performance, geomembrane is widely used in the liner system of municipal solid waste landfill together with geotextile as a protective layer. The relatively low shear strength of the interface between geomembrane and geotextile contributes to the formation of a potential slip surface within the liner system, which may result in instability of the landfill. In the present study, a new technology of direct shear test was developed, including a newly designed experimental apparatus and corresponding testing methods. A series of large-scale direct shear tests were performed to measure the interface shear strength between a smooth/textured geomembrane (GMS/GMX) and a non-woven geotextile (NW GT) under monotonic loading with three levels of normal stresses (σn = 100, 250, 500 kPa) under high shear rate of 100 mm/min. The experimental data indicate that the shear strength of GM/GT interface mainly depends on the normal stress, and shear distance. In general, these large-scale direct shear tests have revealed the complex intrinsic relationship among peak and residual shear strength, normal stress level and types of interface.