ABSTRACT
In today’s world, mechanically stabilized earth (MSE) walls have become a widely accepted technology, effectively replacing traditional gravity and semi-gravity concrete retaining walls. The stability of MSE walls mainly relies on the interaction between the reinforcement materials and the fill soil. This interaction is typically assessed in the laboratory through pullout and direct shear tests, which use a single-layer geogrid arrangement. However, various geogrid configurations are employed in practice, including spreading two layers of geogrid in a trapezoidal shape, by increasing the contact area with the soil. Accordingly, the objective of this study is to investigate the influence of spread ratio on interface direct shear and pullout test results of geogrid. The results of pullout and direct shear tests revealed significant differences in pullout resistance factors and peak shear strength parameters corresponding to different geogrid spread ratios for a given sandy fill material.
