Assessment of pegged geogrid (PG) pullout performance in coarse-grained soils using PIV analysis

Abstract

The paper examines the efficacy of using small, welded metal plates (pegs) in enhancing the pullout resistance of commercially available geogrids. Soil deformations and particle displacements at the soil-geogrid interface and in the vicinity of the pegs were investigated using the Particle Image Velocimetry (PIV) technique. Effects of the soil particle size, overburden pressure, and the height and locational arrangement of the pegs were examined. Results indicate the effectiveness of pegs in enhancing geogrid pullout resistance, which increases significantly with peg height and the distance from the pullout load. Meanwhile, the PIV images showed larger soil strains and particle displacements in coarser soils and under greater overburden pressures. Results also indicate that taller pegs are more effective in engaging the soil adjacent to the reinforcement layer, resulting in reduced particle displacements and increased passive resistance of a larger volume of soil, leading to greater pullout resistance. Findings of the study can be beneficial in practice where pegged-geogrids of reduced length could be used to meet design requirements while addressing space limitations and/or excavation costs, and thereby, help with the feasibility and cost-effectiveness of MSE walls and reinforced slopes in related projects.