Estimation of Dynamic Interfacial Properties of Geosynthetics

The dynamic frictional properties of different geosynthetic interfaces play an important role in the stability analyses of various geotechnical structures that incorporate geosynthetics. The paper presents and discusses laboratory test results on eight different interfaces, formed through various combinations of three geosynthetics (a geotextile, a smooth geomembrane, and a geonet). The dynamic frictional properties were estimated using cyclic direct shear tests, shaking table tests conducted at a normal g-level of 1g as well as at high g-levels, and on a 100 g-ton geotechnical centrifuge. The centrifuge simulated high normal stress levels, commonly encountered by geosynthetics comprising base liners of landfills or base isolators for large structures. The tests revealed various important characteristics regarding the dynamic frictional properties of the geosynthetic interfaces, including a dependence of some of the interfaces on the level of normal stress and the excitation frequency. It is felt that these differences should be considered when selecting proper test methods in relation to the application for which the geosynthetic is considered. It was concluded that proper simulation of field conditions in laboratory experiments is important to obtain suitable friction angle values to be used in design.