ABSTRACT
Finite Element Analysis (FEA) validated by physical testing was used to demonstrate the significance of the transfer of applied surcharge outside the punching shear mechanism in the granular layer to the extent that it becomes a favourable load counterbalancing bearing capacity mechanisms in the clay subgrade. The installation of geogrid in the granular layer was demonstrated to enhance the surcharge transfer, giving rise to much improved bearing capacity, particularly on soft subgrades. A parametric study by FEA identified a simple, linear relationship between bearing capacity and geometry. This could be used in routine design calculations for granular layers with and without geogrid, once the single load transfer efficiency parameter has been established for the granular layer and specific geogrid product (if any) by testing and FEA parametric study.
