The Florence High-Speed Rail project is part of the complex retrofit infrastructure program of the high-speed railway network that will run between Milan and Naples in italy. The project has a total length of 16km and is mainly characterized by three functional components: the underpass, which is composed by 5km twin-bored tunnels (for a total length of 10km), constructed using a TBM machine which has a diameter of 9,4m, and by two SEM tunnels; the new Belfiore underground station, constructed with the top-down technique; and the overpass, which facilitates rail traffic between the two stations of Firenze Castello and Firenze Rifredi.
The new underground line crosses the city centre of Florence, running under more than 200 historical buildings (e.g. a 16th Century fortress). That’s why particular attention was paid to design passive and active protection measures (e.g. DSM, soil freezing technique).