Prediction of Settlement of Pile Groups

The interactions among closely located piles are complex in super-long pile groups. Few data are available on the testing of full-scale bored pile groups in the field. To investigate the behavior of super-long bored pile groups, axial static load testing of in-situ and full-scale instrumented pile groups and single piles were performed. An alternative to modeling pile interaction and calculating individual pile response is to model the pile group as a single foundation unit in what is referred to as the equivalent pier method. Based on nonlinear pile-soil-pile interaction modeled by hyperbolic load-transfer functions and the group effect of reduction of stiffness and increase of head settlement, it was found that the initial stiffness reduction coefficient β of 0.3 is suitable while the value of g ranges from 0.15 - 0.4 for this field tested pile group.