Evaluation of sand–geosynthetic interface behavior for earth reinforcement

Abstract

For the effective use of a geosynthetic material in earth reinforcement, along with mechanical properties the interaction behavior of geosynthetic with backfill material has significant importance regarding safety analysis. This paper investigated the interface behavior of a new type of geosynthetic, made of Basalt fiber, with sand through a series of direct shear tests. In the tests, the applied normal stresses were varied from 40 to 160 kPa. The test results reveal that the shear strength of all sand-geosynthetic interfaces increased with the increasing normal stresses. The geogrid having small apertures and thin ribs shows the maximum interface shear resistance whereas the sand-geotextile interface shows significantly lower shear resistance comparing to that of sand-sand interface. Strain hardening–softening behavior is clearly observed for the sand-geogrid interfaces, but the geotextile interface shows no softening behavior after the peak. It is also observed that the presence of sand in the apertures of geogrids dominates the dilatancy behavior of the sand-geogrid interfaces. The average interface efficiency of the sand-geogrid interfaces tested in this study is found ranging from 0·61 to 0·87.