Geosynthetic/Soil Interface Friction Angles Using a Rotation Shear Device
A modified rotation shear device was used for measuring interface friction angles between soils and geosynthetics. The device was modified so that a geosynthetic specimen can be attached to the upper platen. A reliable method for cutting and attaching geosynthetic specimens to the device is described. The geosynthetic mounting system is simple, strong, and easy to remove. Interface friction angles and interface efficiencies for two ash samples and Boston Blue Clay with three geosynthetics are reported and compared. A range of strength increase is reported for a given soil with change from a smooth geomembrane to a textured geomembrane or nonwoven geotextile. Shear displacements up to 300 mm are quantified in the paper, showing that large, unidirectional displacements may accumulate in the rotation shear device.