Abstract: Textured geomembrane (GMX) and non-woven geotextile (GT) are important components of the liner system in MSW landfills. GMX-GT interface characteristics are sensitive to the stability of landfills. However, the dynamic behavior of the GMX-GT interface is not well understood. A series of cyclic direct shear tests was conducted on the GMX-GT interface under dry and fully saturated conditions. The effects of vertical stress, displacement amplitude, and cycle times on the dynamic behavior of the GMX-GT interface were studied. The dynamic behaviors of the GMX-GT interface under dry and fully saturated conditions were compared. The results demonstrated that the GMX-GT interface changed from shear hardening to shear softening with the increase of displacement amplitude. Meanwhile, the internal friction angle of the GMX-GT interface increased with the increase of displacement amplitude due to the cyclic shear. The GMX-GT interface was mainly characterized by shear shrinkage. The total shear shrinkage increased with the increase of vertical stress, displacement amplitude and cycle times. The shear stiffness increased with the increase of vertical stress and cycle times, while decreased with the increase of displacement amplitude. The damping ratio increased with the increase of displacement amplitude and decreased with the increase of cycle times, indicating that the displacement amplitude increased the energy dissipation of GMX-GT interface. The failure pattern was obvious different under the two conditions. The internal failure of GT was more significant under dry conditions, and the surface failure of GMX was more obvious under fully saturated conditions.

Key words: geomembrane-geotextile interface, cyclic shear test, dynamic shear characteristics, shear stiffness, damping ratio