What value of interface friction to select for geosynthetic liner on landfill slopes?.

To characterize the geosynthetic friction, the Inclined Plane is recognized as a very suitable and versatile device, since it allows to test large samples with variable relative tangential displacements under low normal stress. According to different studies carried out in France, the procedure proposed by the European Standard could provide non-conservative results. For this reason, two alternative procedures are proposed: the “Displacement Procedure” and the “Force Procedure”. In this study a full description of the two procedures is presented and an application to a typical landfill barrier interface is carried out. Furthermore, several values of the interface friction angles are determined from the two methods and a comparison with the “standard” value is provided.