Numerical study of vibro-driven pile installation in sand

Vibro-driving of monopiles is increasingly being considered as it offers advantages of lower acoustic emissions compared to impact-driven piles, rapid installation particularly in sand but also mitigation of the risk of pile run
as the pile and vibro-driver remain connected to the crane at all times. Numerical modelling offers the opportunity of providing additional insights that are difficult to obtain through physical modelling, including observation of changes in soil state. Vibro-driving of large diameter thin-walled open-ended cylindrical piles into saturated sand is, in numerical modelling terms, a boundary value problem involving very large deformations (with target penetrations hundreds of times the pile wall thickness), requiring coupled pore fluid-stress analysis with an effective stress-based soil constitutive model that captures
the stress and state dependent behaviour of sand. Coupled Eulerian-Lagrangian analysis (together with user-defined routines) has been used here to perform these analyses. Using this approach, this paper explores the complex inter-relation of parameters that can be controlled in vibro-driving and the resulting changes in the pile penetration, which are underpinned by cyclic, dynamic and drainage effects.