Load Carrying Mechanism of Geocell Reinforced Embankment on Soft Soil

Abstract

This paper investigates the influence of geocell reinforcement on the load carrying mechanism of embankments over soft soil. Using a geocell mattress beneath an embankment on soft soil, the size of the rupture zone in the foundation bed is found to have increased significantly, leading to increase in the mobilized shear resistance, and giving rise to enhanced bearing capacity. While the unreinforced embankment, owing to differential settlements, tends to crack and disintegrate, the geocell reinforced embankment continues to behave as a monolith up to a high surcharge pressure/fill height. The performance improvement tends to increase with increase in height of the geocell mattress. Strain variation in the geocell mattress indicates that its reinforcing efficacy is the largest at the central crest region of the embankment and decreases toward the toe. As the geocell mattress behaves as a semirigid slab, when it is present, the stress dispersion angle tends to increase significantly. Considering the stress dispersion zone as an equivalent rigid footing, the bearing capacity of unreinforced and geocell reinforced embankments are analyzed. The predicted bearing capacities are found to be in close agreement with the experimentally observed ones. Three-dimensional numerical analyses indicate that the pressure–settlement behavior of the embankments observed in the model tests is reproduced at large scale.