Interface Properties of Metal-Grid and Geogrid Reinforcements with Sand

Reinforced earth or soil structures are becoming increasingly popular in the present day. For proper design of any reinforced structure, it is important to study the soil-reinforcement interface properties. The interaction mechanism can broadly be classified into two types: direct shear mechanism and pullout mechanism. In this study, tests were performed as per ASTM D5321 to study the interface characteristics of two types of reinforcements commonly used in practice (geogrid and metal grid) with Indian standard sand. A large-size direct shear test apparatus of dimensions equal to 300 mm x 300 mm x 200 mm (in length, width, and depth) is used in the study. Pluviation method is adopted to prepare uniform sand samples with a relative density of 90%. This paper provides details on sample preparation and interface properties of two types of reinforcements with sand material. Based on the test results, the average interface shear strength coefficients of geogrid-sand and metal grid-sand are found to be equal to 0.88 and 1.02 for the normal stresses considered in the study. These coefficients are in good agreement with the results reported in the literature.