Evaluation of the Settlement of Embankment Supported by Cast-in-Place Concrete Tubular Piles

Cast-in-place concrete tubular piles have been recently introduced into road construction to serve as ground-improving columns that sustain a considerable portion of the embankment load. With respect of the characteristics of such piles in geometry and stiffness, traditional settlement-predicting approaches for composite ground may be no longer suitable. This study discusses the load-carrying behavior of composite ground with particular focus on the variation in the load share of piles. Based on the Mindlin's and the Boussinesq's solutions, a new model is developed to calculate the additional stresses generated respectively by the resistances of pile base, pile shaft and soil plug, as well as the surcharge directly acted on the ground. A case history is presented to demonstrate how the model works and also to examine the consistency between the measurements and predictions.