By rosebell
In order to advancing the Catania Metro in Sicily, a Herrenknecht variable density TBM passed its Factory Acceptance Test last week.
The responsibility of deploying the machine on the metro section between Misterbianco and Paternò, and an additional section between Monte Po and Misterbianco, which links to an existing line, will be up to SIS, a Finninc and Sacyr joint venture.
Considering that the project is close proximity to Mt Etna, a variable density TBM was specified, whereas subsoil in the volcanic area is highly variable and both temporary and permanent works must meet strict seismic standards.
According to Tunnel manager for the project, Miguel Ángel Montón: “A metro project undertaken in the city several years ago used a conventional TBM and encountered significant difficulties due to the unfavourable geological conditions. The ground is extremely complex due to its heterogeneity; there are fissures, cavities, and frequent alternations between basaltic rock – lava – and softer soils. Our TBM is highly adaptable to current conditions; its operating mode can be changed on the fly using four different excavation modes, allowing us to respond in real time to the terrain. It is more complex to operate, but offers that flexibility.”
With the aim of being transported to the construction site, the TBM is now going to be disassembled and the scheduled date for its arrival is July.
Benefiting special convoys, the heaviest components are due to be transported across the Alps to the port of Ravenna in Italy, from where they will be shipped to Catania, while the smaller components will be transported by truck across the Strait of Messina to Sicily.
While the required time for on-site assembly of the TBM will be almost three months, approximately two weeks is needed for launching and testing and the expected date for commencing excavation is the end of December or early 2026.
The TBM will excavate a total of just over 5km on both sections.
