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 R² 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.

KEYWORDS:

• Load–transfer methods
• hyperbolic model
• granular soils
• pile groups
• deformation parameters

Acknowledgments

The authors would like to thank the Post-Graduate Program in Civil Engineering (POSDEHA) and the Department of Hydraulic and Environmental Engineering of the Federal University of Ceará for encouraging and supporting this research, and to the Brazilian Federal Agency for Postgraduate Education (CAPES) and the Brazilian National Council for Scientific and Technological Development (CNPq) for the financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets analysed during the development of this research are not yet publicly available but will be in the next few months at the institutional repository of the Federal University of Ceará. The analysed datasets will be available upon reasonable request to the corresponding author.

Author contributions

All authors significantly contributed to the conception and development of the research that led to this paper. Data gathering and analysis were carried out by Danton França da Silva. Supervision and manuscript review were carried out by Alfran Sampaio Moura. All authors read and approved of the final version of this manuscript.

Additional information

Funding

This research was supported by the Brazilian National Council for Scientific and Technological Development (CNPq), through the granting of a scholarship to the corresponding author, Danton França da Silva.