Influence of subgrade strength on the performance of geocell-reinforced foundation systems

ABSTRACT: Physical model tests were performed on geocell-reinforced foundation systems with circular footings to study the influence of the strength of the subgrade layer. Model tests were conducted with a 150 mm diameter circular footing supported on foundation beds with varied configurations. Three different series of tests were conducted using a clay subgrade with undrained cohesion in the range of 7–60 kPa and dense sand at 80% of relative density. The results showed that the performance of the geocell-reinforced foundation systems was highly dependent on the subgrade strength. A maximum improvement factor of about 11.6 was observed for very soft subgrade with cu= 7 kPa, which decreased to about 3 for stiffer subgrade having cu= 30 kPa under similar test conditions and configuration. In addition, the variation of bearing capacity improvement factors was observed to be significantly influenced by footing settlement and geocell height.