Development of an analytical model for nonlinear vertical load transfer in screw-groove piles considering cross-sectional characteristics

Conventional pile foundations for offshore structures face challenges with bearing capacity and material efficiency in harsh marine environments. Screw-groove piles are an innovative prefabricated solution, offering enhanced load-bearing capacity, cost-effectiveness, and environmental sustainability owing to their unique screw-groove structure. Nevertheless, the complex interaction between the piles' screw-groove section and surrounding soil means that existing soil-pile interaction models cannot adequately capture their load-transfer mechanisms. This study develops a nonlinear axial load-transfer algorithm for screw-groove piles incorporating sectional characteristics. The cross-sectional area, perimeter, and moment of inertia of screw-groove piles were derived considering the groove parameters. By utilizing hyperbolic functions to simulate interactions at the pile shaft and tip, a shaft resistance calculation method that integrates the critical pitch based on Meyerhof's theory was formulated. Subsequently, a nonlinear piecewise displacement-compatibility iterative algorithm for the settlement prediction of screw-groove monopiles was developed. The analytical results agreed well with experimental data, and three-dimensional finite element analyses confirmed the accuracy of the model. This novel analytical framework that integrates both the cross-sectional properties and critical pitch effects provides a theoretical basis for enhancing the performance of screw-groove piles under axial loading.