Settlement and Load Distribution Analysis of Pile Groups

Abstract

Analyses are made of the settlement interaction between two compressible floating piles in a semi infinite mass, and between two compressible piles resting on a rigid bearing stratum. The results of these analyses are expressed in terms of interaction factors relating the increase in settlement due to the second pile to the settlement of a single pile. It is shown that, as previously found with incompressible floating pile groups, the interaction factors for two piles may be superposed to analyse the settlement and load distribution within any compressible pile group. The influence on group behaviour of the compressibility of the piles relative to the soil is examined for square groups of piles. It is found that, for a floating pile group, the settlement interaction decreases as the piles become relatively less compressible, and for a group with a rigid pile cap, the load distribution within the group becomes more uniform. In contrast, for a group of end bearing piles, the settlement interaction increases as the piles become relatively less compressible while the load distribution within a group having a rigid cap becomes less uniform. Comparisons between theoretical group behaviour and that observed from model and field tests generally show good agreement (a).