A comparison of static and cyclic loading responses of foundations on geocell-reinforced sand

The results of laboratory-model tests on strip footings supported on unreinforced and geocell-reinforced sand beds under a combination of static and repeated loads are presented. The influences of various parameters are studied including reinforcement width, height of the geocell below the footing base and various amplitudes of repeated load. Mostly, a stable, resilient response is observed once incrementally accumulated plastic strain has ceased (usually during the first 10 cycles of loading). The reinforcement reduces the magnitude of the final settlement, acts as a settlement retardant, permits higher loads or increased cycling. The reinforcement’s efficiency in reducing the maximum footing settlement decreased as the height and width of geocell were increased. Plastic deformation was limited by geocells more under repeated loading than under a similar static loading, with the reduction being greatest when more reinforcement was present and when the loading rate was fastest. It is deduced that the greater resilient stiffness of a rapidly loaded polymeric geocell attracts load to itself thereby protecting the soil from some of the more challenging stress states and, hence, reduces deformation. Simple dimensional analysis showed the need for an increased stiffness of the geosynthetic components in order to deliver full-scale performance similitude.