A 1g model experimental study on the effects of installation parameters on vibratory driving performance of monopiles

Monopiles are a common foundation type for offshore wind turbines. Compared with the traditional impact driving installation methods for monopiles, vibratory driving is a promising alternative with advantages of rapid installation, low acoustic noise emission and limitation of stresses during driving. However, uncertainties over vibration parameter effects on driving performance may prove a barrier to widespread adoption of purely vibration based installation. This paper presents preliminary 1g results of an experimental model investigation into these uncertainties. A series of preliminary 1g reduced scale tests were conducted to drive an instrumented model pile in dry medium-dense and dense sand. A mini vibration unit with exchangeable eccentric masses was used to install the pile. The frequency and the force generated by the vibratory driver can be controlled by changing the eccentric masses and electrical power supplied, in which the driving performance under different vibration controls was recorded. The preliminary results indicate that the ultimate installation depth and the driving velocity are influenced by the combined factors of frequency and driving force, and it appears that frequency plays a more significant role in determining installation performance.