Response of High-Density Polyethylene Geomembrane–Sand Interfaces under Cyclic Shear Loading: Laboratory Investigation

Abstract

Geomembranes are thin polymeric sheets used as barriers to liquid or gas intrusion in earth structures due to their low permeability. The mechanical behavior of geomembrane-soil interfaces plays an important role in the stability analysis of geomembrane structures under cyclic loading caused by an earthquake or traffic. In this study, a series of cyclic shear tests were conducted using a large-scale direct shear apparatus to observe the cyclic shear response of geomembrane-sand interfaces, with emphasis on vertical displacement and cyclic shear stiffness. The influences of vertical pressure, geomembrane texture, and cyclic shear loading form on the cyclic shear behavior of geomembrane-sand interfaces were examined. The cyclic shear stiffness showed an increasing trend with increasing vertical pressure, but significantly decreased with increasing shear-displacement amplitude. Textured geomembranes can effectively improve the cyclic shear strength of geomembrane-sand interfaces. The volumetric behavior of geomembrane-sand interfaces is evidently dependent on the form of cyclic shear loading and the magnitude of applied vertical pressure. The cyclic shear behavior of pure sand was also compared with that of geomembrane-sand interfaces.