The first access of the "Aurora" TBM to the excavation chamber of the Grottaminarda tunnel, the first of three tunnels along the Apice-Hirpinia section - an integral part of the new HS/HC Naples-Bari line - was performed in hyperbaric mode.
The preliminary activities prior to the start of excavation benefited from the synergic dialogue between the Contractor's team and the Works Supervision conducted by Italferr, the engineering company of the FS Group's Infrastructure Hub.
The experience gained by Italferr technicians in the field of mechanised excavation in Sicily, first at the Ogliastrillo-Castelbuono site and later at the Giampilieri-Fiumefreddo Lot 2 site, was crucial in defining the operating procedures useful for ensuring safe access to the TBM.
The technical morphology of the ground led Italferr to the decision to use a Tunnel Boring Machine (TBM) that excavates in Earth Pressure Balance (EPB) mode to avoid subsidence above the excavation and not alter the tensional state of the surface.
The 'Aurora' mechanical mole has two internal hyperbaric chambers, both equipped with individual seats and respective oxygen breathing circuits, which allow the initial compression phase and the subsequent decompression phase.
Each phase is always supervised by a hyperbaric technician, the hyperbaric manager and the hyperbaric specialist physician.
The outcome of the verification activities was carried out successfully without any unforeseen problems or criticalities with respect to the implementation of the prescriptions set during the coordination phase.
Once again, Italferr's expertise allowed the achievement of an important goal that adds a further milestone to the realisation of one of the most strategic routes for Italy.