Influence zone around a closed-ended pile during vibratory driving

Abstract

This paper presents a numerical study based on vibratory driving of closed-ended piles. A set of axisymmetric finite element models were used to replicate the wave propagation during vibratory pile driving and to investigate the effect of wave propagation on the surrounding ground. The numerical modelling technique adopted for the analysis takes into account the large soil deformations around the pile during driving and is based on the Arbitrary Lagrangian Eulerian technique. It has the ability to drive a pile few pile diameters below the initial position without mesh distortions and the numerical model was verified using field data available in the literature. Soil was modelled as an elastic-perfectly plastic material. A parametric study was performed to determine the influence of change in pile driving force on the far field using different operating frequencies and amplitudes of the driving force, and rigidity index and material damping of the surrounding soil. The parameters for the driving force were extracted from the published specifications of commercially available vibratory piling rigs. Finite element results were compared with ground vibration measurements of peak particle velocities during vibratory sheetpile driving found in the literature. These results show that the material damping is an important parameter contributing to wave attenuation around the driven pile in addition to the geometric damping. The impact on the far field is discussed comparing the peak particle velocity distributions with the specifications given by the American Association of State Highways and Transportation Officials (AASHTO), Swiss Standard SN640312 and Eurocode 3 for acceptable vibrations to avoid damages to existing nearby structures. Finally attenuation relationships, and upper and lower bounds for the peak particle velocity distributions around a driven closed-ended pile are presented to determine the influence zones for different types of nearby structures.