Evaluation of fitting to hyperbolic functions of load transfer curves for piles in granular soil profiles

ABSTRACT Load–transfer methods are important tools to analyse and predict pile settlements. Several studies on single piles and pile groups used experimental data from instrumentation, in order to evaluate the load–transfer mechanism to the foundation soil, by obtaining skin friction and toe resistance. For single piles, the load–transfer curves can be approximated by hyperbolic models, and for pile groups, by models in which the interaction between nearby piles is added to the hyperbolic curve of each individual pile through analytical formulations. By collecting experimental data from 68 piles executed in granular soils that were instrumented and subjected to static load tests, this study evaluated the fitting of load–transfer curves to hyperbolic functions for single piles and pile groups. Remarkable fitting to hyperbolic functions was found for single piles, and very good agreement was also obtained for pile groups (adjusted R 2 around 0.96). The deformation parameters (M s and M b) by Bohn et al. for single piles were reassessed, and new reference values that led to more convergent predictions were proposed. Lastly, the use of the parameters M s and M b was also extended to pile groups and new preliminary reference values were suggested.