Soil-geogrid interaction in the inclined plane shear movement

Abstract

Inclined plane tests are commonly performed to study the interaction mechanism at soil-geosynthetic and geosynthetic-geosynthetic interfaces which are located over sloping surfaces and where the shearing is the relative movement most probable to occur. In this study, the interaction between a residual soil from granite and a biaxial woven geogrid in the inclined plane shear movement was analysed through a series of inclined plane tests performed according to EN ISO 12957-2:2004. In order to investigate the influence of the applied vertical stress, soil moisture content and soil dry unit weight on the interface behaviour during the inclined plane shear movement, inclined plane tests were carried out with different values for those parameters. A different approach to define soil-geogrid interface shear strength parameters based on the Mohr-Coulomb failure envelope was considered and the results were compared with those obtained through the conventional methodology. For a better understanding of the interface behaviour during the sliding process and to distinguish interfaces which exhibited similar slipping angles but different behaviours until the target displacement of 0.050 m was reached, two characterisation parameters were introduced. Results showed that the interface friction angle, when determined by the conventional method, was significantly influenced by the applied vertical stress, soil moisture content and soil dry unit weight.