Compaction-induced prestressing effect of geocell reinforcement

The loading and unloading actions of rollers during the construction of geocell-reinforced soil subgrade lead to the compaction of infill materials, which further causes the geocell pockets to expand. Due to the pre-tensioning of the geocells, such responses result in increased lateral confinement of the infill soil prior to the service of the geocell-reinforced soil subgrade. The phenomenon was defined as the Compaction-induced Prestressing Effect (CIPE) in this paper, which was verified through the finite difference method-discrete element method (FDM-DEM) coupling numerical simulations on reinforced subgrade with the aid of FLAC 3D and PFC 3D software. An equation was proposed to quantitatively describe the influence of CIPE on the initial stiffness of the reinforced subgrade. Furthermore, experiments and numerical simulations were employed to investigate the evolution of Modulus Improvement Factor (MIF) values over time, where the rheological properties of geocells were considered. The findings indicated that geocell sheets experienced a normal deformation of approximately 0.5 mm and tensile strains ranging from 0.17% to 0.21% following vibration compaction. The MIF values ranged from 2 to 6 due to CIPE. When the prestressing strain of the geocell sheet reached 0.1%, the geocell strain stabilized within 300 seconds, with the MIF decreasing by 27.6%.