Laboratory studies of interaction properties between fine sand and various grid reinforcements

Geogrid and steel mesh have been significantly used for reinforcing the soil as extensible and rigid reinforcements, respectively. This research evaluates the effectiveness of two methods to improve the interaction properties between these reinforcements and poorly graded fine sand by laboratory tests. For increasing the contribution of transverse members of geogrid to shear strength along the geogrid–soil interface in direct shear test, transverse steel bars were added to geogrid and geogrid–bars system was made that here is called G-B. Corrugated bars were also used as steel mesh members to increase the contribution of longitudinal members to pullout resistance of steel mesh. Results of nine direct shear tests performed on a sample of G-B were compared with that obtained from pullout tests presented by Mirzaalimohammadi et al. (Geotext Geomembr, 2019). Direct shear strength of G-B under three different vertical pressures was determined about 42% greater than that of ordinary geogrid. It showed the higher efficiency of transverse bars in direct shear tests than that of 26% obtained from pullout tests. In addition, six pullout tests were conducted to compare the performance of corrugated and ordinary steel meshes. Corrugated steel mesh exhibited larger pullout resistance and strain than that of ordinary mesh. The efficiency of G-B and corrugated steel mesh increased with increasing the vertical pressure.