Enlargement construction works for a section of Lapa Railway Tunnel, which integrates the intersection works between Line J and Line C Tunnels of the Metro of Oporto. The enlarged tunnel is 72 m long. Construction of a section of Lapa Railway Tunnel, on Line J, of the Metro of Oporto. The tunnel is 278 m long. The excavation section is about 31 m2. Excavation: 12.888 m3. Shotcrete: 3.341 m3.