On the interface shear resistance of a novel geogrid with in-plane drainage capability

The enhancement in the short-term interface shear strength (critical case for embankment construction) achieved by a novel geogrid that combines both reinforcement and in-plane drainage functions was studied. Marginal fill (wet gravely clay) was standard Proctor compacted to 92% of its maximum dry density and tested under consolidated-undrained conditions in the large shearbox apparatus. The interface shear resistance (τ_s-g) values mobilized for the novel geogrid were similar to the undrained shear strength of the surrounding soil. In contrast, the τ_s-g values mobilized for a conventional geogrid, which had similar physical and tensile strength properties, were only between 82% and 85% of the undrained shear strength of the soil. Overall, the undrained shear resistance mobilized along the soil-geogrid interface was between 20% and 30% greater for the novel geogrid than for the conventional geogrid.