Contractor CMC di Ravenna will navigate the variable soft ground geology along the project alignment, which ranges from silts to sandy silts with some cobbles expected.
The TBMs are 4.66m-diameter EPBMs with a spoke cutterhead design with a 49% opening ratio. Tools are fixed and back-loading knife bits.
The tunnel will be excavated at an average depth of 25m, beginning with an approximately 400m radius curve and continuing along an essentially straight alignment, reaching a maximum slope of +/- 2.0%. As the machine progresses, it will install a precast concrete segmental lining ring consisting of six (four parallelograms and two keys) 250mm thick, 1400mm wide, segments.
