Trevi is working at the "Darsena di Levante" eastern dock in the port of Naples to the design and realisation of a new container terminal, a wide area created by filling the body of water between the two piers. From an operational point of view, the project has to face major environmental and construction challenges, due both to the position on the sea and the environmental requirements to be met. A cofferdam structure has to be constructed to the seaward and the landward side, which requires the use of some of the most cutting-edge technologies and materials existing today, from sheet piling to the consolidation of the seabed level, from low impact concreting plants to fibreglass pipes and special cements.
Envisaging the creation of a container terminal extending over an area of 230,000 sq.m with a 672 m-long quay, this rehabilitation and rationalisation project will have a major impact on the city, giving a new momentum to the commercial and container industry. As a result, Naples will continue to play an important role in Southern Europe.
For the landward portion, the piles of the cofferdam structure are constructed using the cased secant piles (CSP) technology in order to create a continuous and watertight diaphragm wall, regardless of the excavation geometry, having a thickness of at least 70 cm. The piles are installed at depth of 24-25 m – some of them even as deep as 28 m – so that they are securely driven into the tufa layer. A system of structural diaphragm walls is also envisaged between the landward diaphragm wall and the quay, to be constructed using the hydromill technology. This solution is more robust, as it is not only intended to cut off the cofferdam structure, but it also has to stand the berthing of large vessels and the weight of gantry cranes.
Major consolidation works are also foreseen at the seabed level under the quay, over a 30m area between the two double walls, using the "Discrepiles" or Displacement Pile technology. Designed by the Trevi Group, it is a special technique that allows to perform compaction without soil extraction, through the combined action of a double tool and jet grouting that together ensure soil compaction and consolidation between adjacent rows of piles.