A series of model tests was carried out to determine the distribution of load among piles grouped in sand. The effects of initial sand density, pile roughness, driving order, spacing, and the position of the pile in the group on the load distribution were studied. The results showed that, for small loads, the load distribution was random. As the load increased, the distribution was governed mainly by the driving order, but as the ultimate group load was approached the effect of driving order diminished and the position of the pile in the group became the predominant factor on which the load distribution depended.In general the centre (or centre core) piles of a group carried the greatest proportion of the load at the ultimate group load while the corner piles carried the least proportion. Beyond the ultimate group load, there was a redistribution of the load in such a way that all piles carried an approximately equal share of the load irrespective of their driving order and position. As the spacing was increased, the distribution tended to become independent of both driving order and pile position, and all piles carried an approximately equal share of the load. Initial soil density, pile roughness, and group size were found to affect the total group loads, but had no effect on the load distribution.
Numerical modelling of perimeter pile groups in clay
