2018
Barberino del Mugello
Autostrade S.p.A.
Pavimental
Spea
THE BOSCACCIO TUNNEL CASE
Challenge
The Boscaccio tunnel, located on the A1 Milan-Naples highway, is part of the extension to a third lane along the Barberino-Firenze Nord section, which began excavation in June 2023. This significant geological context lies between two major Apennine tectonic geosynclines: the Mugello Area to the north and the Firenze – Valdarno Area to the south.
The geological section, traversed by the tunnel, is characterized by flysch sequences, including the Monte Morello and Sillano Formations. These formations involve rhythmic lithologies of marl, limestone marls, and claystones, and span a cover range of 10 to 60 meters.
Solution
In response to demands for enhanced safety, particularly in the case of the Boscaccio Tunnel, an innovative primary lining reinforcing system has been implemented. This system features the automated Round Tubular tunnel rib, introduced by the EKIP 21-04 installation system, providing a circular design and shotcrete filling. This rib, which spans 32.7 meters in the tunnel section, offers greater structural strength and requires 14% less shotcrete spray during processing, significantly advancing tunnel construction technology.
The Boscaccio Tunnel’s excavation experience, spanning 1962 meters, has allowed for detailed analysis of the time and material savings compared to traditional rib installation methods. Notably, the automated installation and connection of the tubular rib save about 30 minutes per rib, translating to nearly 41 working days saved over the course of the tunnel’s construction. Moreover, the automated system, operated by a single operator during specific work phases, reduces the need for multiple operators and machinery, effectively minimizing potential downtime and maximizing economic savings.
Underground construction is inherently dangerous, often conducted in noisy, confined spaces with moving heavy machinery. The use of this technology eliminates the need for worker presence near the excavation face, significantly increasing safety levels. This approach not only leads to economic savings but also minimizes environmental impact and material wastage, underlining the possibilities of enhancing safety through innovative solutions.
