Mechanical properties and failure characteristics of geocells: A comparative experimental study

The tensile performance of geocells depends on the mechanical responses of both cell walls and junctions. Three commercial geocells, liquation-welded polypropylene (LW), injection-molded polyester (IM), and ultrasonic-welded high-density polyethylene (UW), were examined through tensile testing, macroscopic observation, and scanning electron microscopy of cell-wall fracture surfaces. Five configurations were used: cell-wall tension, junction-inclusive tension, and junction seam, shear, and split tests. The cell-wall peak strengths of LW, IM, and UW were 143.03 ± 4.43, 185.61 ± 7.96, and 39.42 ± 2.41 kN/m, respectively. Including a junction changed the strengths by +28.99%, -59.79%, and -23.76%. The LW and IM cell walls lost load rapidly after the peak. UW exhibited necking and extended post-yield deformation. SEM revealed microfibrillar bundles in LW, a smooth layered surface in IM, and dense drawn microfibrils in UW. Under junction-inclusive tension, LW tore near the raised-tab edge, IM cracked through the ligaments between the holes, and UW fractured at a weld-wall boundary. LW provided the highest seam and shear strengths of 66.16 ± 4.20 and 146.02 ± 8.46 kN/m. IM provided the highest split strength of 158.55 ± 10.34 kN/m. UW showed lower junction strengths but reached 343.09 ± 13.72% rupture strain under shear. Under seam and shear loading, LW failed near the tab-wall transition, while IM fractured from hole edges. UW failed within the weld region under seam loading and at a weld-wall boundary under shear loading. Under split loading, failure occurred at the heat-fused interface in LW, the molded body in IM, and the central weld in UW.