Analytical solution for consolidation of sand‐filled nodular pile (SFNP) foundation and its engineering application

The sand‐filled nodular pile (SFNP) foundation is newly proposed to improve the bearing capacity and accelerate consolidation settlement of foundations installed in soft clay soil. By filling sand while driving the nodular pile into the soft clay soil, the SFNP foundation provides an extra drainage path with the aid of the nodular segment, while maintaining the high modulus reinforcement body at the core of the composite foundation. The performance of the SFNP foundation is greatly influenced by its consolidation behaviour. This study develops a generalized model for the SFNP foundation, and a closed‐form solution is then established considering the smear and well resistance effects. The developed model and the associated analytical solution are employed to investigate the consolidation rate and load distribution of the SFNP foundation. Finally, the analytical solution is utilized to evaluate the performance of SFNP foundation for an expressway project located in Zhejiang, China. The predicted dissipation of the excess pore water pressure employing the developed analytical solution agreed well with measured response from the field test, which further confirmed the advantages of the SFNP foundation and the reliability of the developed solution.