Influence of Torpedo Piles Parameters When Assessing Final Penetration Depths

This paper has been influenced by a basic question: assuming a torpedo pile launching in a base case scenario, which parameters, when not well controlled, would affect more the pile final penetration depth? Aiming to provide an answer to this question, the methodology adopted in this study assumes the application of numerical simulations and statistical analyses in order to quantify the influence of the uncertainties of such parameters in the final penetration depth. From the assessment, one may expect responses in terms of which parameters shall be better controlled during a launching procedure in order to reduce the uncertainties associated to the target depth. For the development of the study, a simplified approach for the dynamic numerical analyses has been adopted in order to allow a massive data generation for the statistical treatment. The main parameters associated to the torpedo pile and the launching scenario have been generated taking into account their uncertainties. The Monte Carlo method has been considered and statistical treatment has been applied to quantify the influence of the parameters in the final penetration depth. The results demonstrate that apply the simplified method described in the paper is adequate to simulate both the subsea free fall and the pile driving phases to obtain the final penetration depths. The torpedo mass has been found as the physical parameter which influences more the final penetration depth. However, the study demonstrates that, given a standard launching procedure assessed by numerical simulations, uncertainties on physical parameters are much less significant for the final penetration depth than the uncertainties inherent to the assumptions and data applied to simulate the soil damping.