Experimental study on mechanical behavior of additive-manufactured geogrid-reinforced sand

This study investigates the innovative application of additive-manufactured (AM) geogrids in enhancing the mechanical behavior of reinforced sand, addressing the limitations associated with commercially available and manually fabricated reinforcements. The novel AM geogrids, integrating the benefits of traditional geogrids and vertical walls, are designed to enhance the performance of reinforced sand. A series of consolidated undrained triaxial compression tests is conducted on both unreinforced and reinforced sand samples to examine the effects of geogrid aperture shapes (square and triangular), number of geogrid layers (single and two layers), geogrid forms (2D and 3D) under varying effective mean stresses (50, 100, and 200 kPa). The findings indicate that the AM geogrid with a triangular aperture shape and a 3D form (T3D), reinforced with two layers on the sand achieves the highest shear strength improvement, showing a 467% improvement under an effective mean stress of 50 kPa. Additionally, the modulus of elasticity notably increased to 9.094 MPa for T3D with two layers under an effective mean stress of 200 kPa, indicating a substantial improvement in stiffness. These improvements can be ascribed to the combined effect of geogrid and vertical walls, where geogrids mobilize shear resistance and interlock sand grains, while vertical walls enhance lateral confinement and passive resistance. The findings provide critical insights for optimizing geogrid design, contributing to advancements in geotechnical engineering and soil reinforcement technologies.