ABSTRACT
This paper describes the main underground works of the Brescia - Verona high-speed/high capacity railway which is part of the new Milan-Venezia railway link. An overview of the design challenges and construction experience of single-bore double-track and twin bored single-track tunnels, bored in urbanized area by traditional excavation technique and by a tunnel boring machine will be shown. For the mechanized excavation of the Lonato tunnel, an EPB TBM with a diameter of 10.03 m are used. In particular, the construction experiences for the first tube completed in September 2022 are discussed. The geotechnical and design challenges are related to the sub-crossings of the A4 motorway with extremely reduced ground overburden, ranging between 7 and 12 m, and large extension up to 425 m. The excavations are carried out in highly heterogeneous geological formations consisting of glacial, fluvioglacial and glacio-lacustrine deposits with very variable permeability values.
