Physical Modelling Of A Caisson Breakwater Under Impulsive Cyclonic Waves : Case Of Port East (Reunion Island)

Abstract

The GPMDLR (Port Authority of La Réunion Island, France) has requested ARTELIA to carry out the preliminary studies for the enlargement of the containers terminal in Port East. In this context, the laboratory of ARTELIA has performed 2D physical model testing to evaluate the behavior of caissons exposed to cyclonic conditions. The solution based on a vertical breakwater has been proposed as an alternative to a rubble mound breakwater given the lack of quarries suitable to provide big quantities of large rocks. Main objectives of the study were: the evaluation of overtopping rates (mean and max), the verification of the stability of foot protection blocks and stones, and the recording of wave pressures (gauges) and loads (scale) on the caissons. Given the fact that most of the waves broke violently upon the caisson, the nature of efforts was impulsive and the scaling to prototype by classical Froude similarity principles was not appropriate. Results were therefore amended following Cuomo’s correction factors for the Froude scaling law (Cuomo et al. 2010). Times series of efforts (forces and pressures) were used to feed numerical models (static and dynamic) allowing for the verification of caissons’ geotechnical stability and the design of concrete parts. This article collects the concerns, feedback and further questioning related to the conducted experiment.