Use of the inclined plane test in measuring geosynthetic interface friction relationship

The inclined plane test is commonly used when studying the stability of sloping geosynthetic liner systems under conditions of low normal stress. Emphasis is placed on analysis of the initial sliding phase in a standard test, prior to reaching the non-stabilised sliding phase, which is generally disregarded by designers. Comparative tests for two different geomembrane materials reveal that it is possible to clearly distinguish different interface behaviours under field conditions. Subsequently, two new test procedures using the inclined plane device are proposed: a creep test that could lead to reconsidering the significance of the threshold angle of friction, ϕgg, determined from a standard inclined plane test; and an abrasion test that could be used when studying geosynthetic slope stability in the field, in order to take into account the geosynthetic laying conditions.