ABSTRACT
To reduce the harmful noise for marine life, generated during impact driving of offshore foundations, vibratory driving was presented as an alternative. Vibratory driving produces less noise and allows faster installation in sandy soil. This technique is cost-efficient for offshore pile installations and causes less pile fatigue than impact driving. One of the main issues with vibratory driving is the lack of a reliable driveability analysis. This is due to uncertainties in understanding of cyclic soil response during vibratory driving and the effect of different vibratory driving parameters on the soil response. In this study Vibratory Cone Penetration Test (VCPT) is used to assess the cyclic soil response during vibratory penetration. VCPT penetrates the soil while inducing cyclic loads and measures cone resistance. VCPTs were conducted in a calibration chamber to investigate the reduction of the cyclic cone resistance due to variation in frequency for the same penetration path. The VCPT results are discussed in terms of acceleration, energy, reduction ratio, which are considered as primary parameters in the different driveability analyses methods. The effect of cavitation during upward movement of the cone is investigated and discussed.
