To further knowledge of the pull-out resistance of grids, a series of pull-out tests was performed in the laboratory. The test regimen included the effects of overburden pressure, grid specimen length and width, and relative density of the sand on the pull-out resistance of the reinforcement. Tests were also performed to find the effect of soil particle size on the pull-out resistance of grids. It was found that the pull-out resistance of grids is a function of the relative density of the soil, the particle size, the length and width of the grid specimen, and the mechanical properties of the grid material. A mechanism of soil-geogrid interaction is described and used to explain the results of the pull-out tests. A significant finding is that the selection of geogrid specimen dimensions for laboratory pull-out tests must take into account the strain to failure of the soil and the stiffness of the geogrid in order to properly represent the maximum pull-out stress that will be available in field applications.
Abstract