FCC Construcción completes the excavation work on the tunnel that will connect Bailén and Ferraz streets, included in the reform of the Plaza de España
FCC Construcción has completed the excavation of the tunnel that will connect Bailén Street with Ferraz, which will be operational before the end of the year. The mayor of Madrid has witnessed the moment in which the north and south mouths of the tunnel have been joined once the work under the archaeological remains of the Godoy Palace has been completed.
The construction method in this section of about 50 meters in length has been different from that of the rest of the tunnel to safeguard the remains of the palace. To carry it out, in the first place, it was necessary to execute an umbrella of horizontal micropiles that would allow the excavation of the tunnel under the ruins without altering them and guarantee their stability before beginning the excavation under them.
Once this structure was implemented, the work continued following the so-called 'Belgian system', a manual method that consists of executing small successive shored excavations to advance the complete vault and limit the open front, in such a way that stability is guaranteed. of the set. Afterwards, the so-called ‘destroza’ is carried out, which is the excavation of the tunnel from the level of the vault (ceiling) to the level of the counter vault (floor) to be able to execute this and the sides.
More than 40 workers have participated in the excavation of this section under the remains, who have manually extracted more than 3,100 m3 of earth, which is equivalent to almost 5,600 tons.
The rest of the tunnel has been made in the open by the so-called ‘cut and cover’ system, consisting of executing two pile walls on both sides of its layout and then the cover slab to later excavate under that slab.