Impact of Peg Geometry and Location on Pullout Forces in Granular Soils

In the current paper, pull-out tests were conducted on granular soils reinforced with pegged geogrid (PG). Granular soils with different particle sizes were reinforced with PG to assess the effects of their geometry and distance from the point of load application on interactions. PG-reinforced samples prepared under the optimal conditions were subjected to different normal pressures. Results showed that increasing soil particle size and normal pressure improved soil-reinforcement interactions at the interface by reducing the tendency of particularly coarser granular soils to dilate. Increasing the geometric dimensions, including the width and height of the pegs, enhanced the bearing surfaces normal to the pullout load application, engaging a larger volume of soil, mobilizing greater soil passive resistance, and subsequently increasing resistance to the pullout of the reinforcement. The results showed that particle size and normal pressures are more influential factors than peg height, length, and distance from the sleeve. The inclusion of pegs resulted in changing the hardening–softening behavior of the OG reinforced samples to total hardening behavior attributed to the mobilization of enhanced soil passive resistance. The PG reinforcement system has shown potential as a suitable, cost-effective, and easy-to-implement method for enhancing interactions in mechanically stabilized earth (MSE) walls.