A numerical study on effects of soil permeability and vibratory parameters on vibro-driving of open-ended piles in saturated sand

Vibro-driving is a promising technique for installing monopiles for offshore wind turbines (OWTs). It offers a faster and quieter alternative to impact hammering, eliminating costly noise mitigation and reducing pile run risk in low resistance soils, enhancing safety and cutting costs and environmental impact. Despite its growing adoption, uncertainties remain regarding the influence of soil and vibro-driving parameters on pile penetration rates and the evolving soil state during installation in saturated sand. This study systematically investigates key factors, including soil permeability, dynamic force magnitude, vibration frequency, and varying hook load, on pile displacement amplitudes, penetration rates, and the underlying changes in soil state using large deformation numerical modeling. Results indicate that lower sand permeability generally leads to higher penetration rates but the response is more complex than drainage analysis based on well-known expressions can capture. Reducing dynamic forces (while keeping the frequency and static force unchanged) decreases pile penetration rates and excess pore pressures. In contrast, reducing the frequency while maintaining the dynamic force ratio results in significantly larger penetration rates due to greater excess pore pressures and consequently reduced vertical effective stresses. • Large deformation FE modelling used to study vibro-driving of open-ended piles in saturated sand. • In clean sand (∼10 −3 m/s), penetration rates are similar to fully drained response. • Lower permeabilities generally increase penetration rates, but trends are not monotonic due to complex pore pressure generation and drainage effects. • Reducing dynamic force while remaining the vibration frequency lowers penetration rates, increases drainage, and limits excess pore pressure buildup. • Lower frequency at a constant dynamic force increases penetration rates, driven by higher pore pressures and reduced effective stresses.