Lateral loading behaviour of vibro-driven and impact-hammered monopiles installed in sand in a geotechnical centrifuge

Vibro-installation of monopiles is an attractive alternative compared to the traditional impact-hammered installation. The advantages include low noise emissions, mitigation against pile run and a potentially faster installation process, leading to a more cost-efficient project. Uncertainties arising from the scarcity of data on the lateral loading performance of vibro-installed monopiles hinder a more widespread use of the technique. This work presents the first evidence of laterally loaded model monopiles installed by vibro-driving in a geotechnical centrifuge, directly comparing the results with impact-hammered tests installed in the same soil sample. Model piles were installed in medium dense sand, under different drainage conditions and vibro-driving parameters. Results show that the vibro-installed piles had similar or stiffer lateral responses compared to impact-hammered piles, with this trend being maintained over the initial monotonic, cyclic and post-cyclic monotonic stages of the tests. A stiffer rotational response was observed for the vibro-driven piles in sand saturated with high-viscosity fluid, while the softest response occurred for impact-driven piles.