Friction at Geosynthetic Interfaces on Inclined Plane Shear

Abstract

This paper deals with inclined plane shear on geosynthetic–geosynthetic interfaces. Soils and geosynthetics properties are referred and test equipment and procedures are briefly described. The geosynthetic–geosynthetic interaction behaviour is studied. The influence of geosynthetic structure, material filling the upper box of the apparatus and soil particle size on geosynthetic–geosynthetic interaction behaviour are discussed by analysing the results of the inclined plane shear tests. The main conclusions that can be outlined from the present study are the following: There is a significant influence of the roughness of the geomembrane on geomembrane–geotextile interfaces resistance. In general, geosynthetic–geosynthetic interfaces resistance are lower when one of these materials is a non woven thermal bonded geotextile. For the woven geotextile, the higher interface resistance was achieved on geotextile–geomattress interface. For continuous lateral surfaces geosynthetic–geosynthetic interfaces a woodblock filling the upper box of the apparatus can be used, as test results are similar to those performed with soil filling that upper box. Soil filling the upper box of the apparatus has great influence on geotextile–geomattress interfaces resistance. This way, for non continuous lateral surfaces geosynthetic (ex: geogrids, geomattress)–geosynthetic interfaces the inclined plane shear test must be carried out with soil filling the upper box of the apparatus. Soil particle size has an important influence on the friction angle of geosynthetic–geosynthetic interfaces.