Abstract:

Sparvo tunnel in Italy, which is bored by an EPB shield with a diameter of 15.55 m and an excavation crosssection diameter of 15.615 m, is one of the largest shieldbored tunnels in the world in terms of diameter. Therefore, there are great risks and technical difficulties in the construction of the tunnel. The following key technologies adopted for the tunnel are presented in the paper: 1) Shield type selection; 2) Design and fabrication of the lining segments, including the concrete mixing proportion, the design and modification of rebar arrangement, the segment joints, the waterstop tie, and the precast of the segments; 3) Key shield tunneling technology, including soil conditioning technology, solutions for flammable mixed air, and “U” turn of shield machine. For the sake of the technologies mentioned, good tunneling result has been achieved. The paper can provide reference for similar projects in the future.

Key words: Sparvo tunnel in Italy, superlarge crosssection shield, EPB shield, shield type selection, segment design