The L9 tunnel boring machine in Barcelona gets stuck and delays the end of the works again

The long history of the works on metro line 9 is made up of an accumulation of delays.

Oliver Thansan
Oliver Thansan
07 April 2024 Sunday 10:22
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The L9 tunnel boring machine in Barcelona gets stuck and delays the end of the works again

The long history of the works on metro line 9 is made up of an accumulation of delays. Two years after the reactivation of the tunnel boring machine after eleven years of paralysis, it is time to add a new setback that has already blown up the Generalitat's plans to open the central section of L9 in 2027.

The tunnel boring machine has been stopped since the end of February about 500 meters from the future Mandri station and will remain there without moving for a few more weeks. Until the end of May, at the earliest. Greater wear than expected on the cutting wheel has forced those responsible for the project to paralyze the machine's progress. For more than a month, the workers have been replacing the teeth of the front shield, since in the current state it was impossible to continue, as La Vanguardia has learned.

“It is a stop that has been decided after encountering more difficulties than expected due to the type of terrain,” sources from the Department of Territory acknowledge. The problems have appeared when the apparently most delicate part from a geological point of view had already been overcome. Now all that remains ahead of him until he reaches Mandri is granite, a very stable material for the tunnel boring machine, but which at the same time causes significant wear and tear due to its hardness.

The objective of those responsible for the work is to get the tunnel boring machine ready over the next few weeks so that it is able to excavate the remaining half kilometer from the place where it is stuck to the well at the Mandri station. It should have arrived there at the end of last year, if the forecasts announced last summer by the president of the Generalitat, Pere Aragonés, and the Territorial Minister, Ester Capella, during a works visit, had been met.

The new deadline set to reach Mandri is throughout the summer, if nothing goes wrong again. It will be then that a much more complete overhaul will be carried out to safely complete the remaining 1.6 kilometers of tunnel to the Lesseps station. The achievement of the goal was scheduled for the end of 2024, although the unforeseen event they have now encountered has blown up the calendar.

In the Department of Territory they avoid setting new dates for this milestone and, consequently, for the completion of L9. They condition everything to a more in-depth analysis of the machine when it reaches the Mandri well. And furthermore, they try to get rid of responsibilities by remembering that "the tunnel boring machine was stopped underground for eleven years due to a political decision and although maintenance work was carried out, it is not a new machine."

Hospi, which is the name of the tunnel boring machine that is boring into the subsoil of the upper part of Barcelona, ​​is the last survivor of the five tunnel boring machines that have worked since 2002 on the L9 works. Twelve meters in diameter and 100 meters long, it has a weight equivalent to four gigantic A380 airplanes, the largest model that can be seen at El Prat airport.

During the eleven years that it was stopped, it was subjected to conservation work that cost 7.5 million euros to prevent it from spoiling the day it returned to work. When the day arrived, after several months of fine-tuning, it was confirmed that it was in good condition to finish the work without having to resort to a new machine. In spring 2022 he returned to working 24 hours a day and at first it even worked better than expected, advancing about 200 meters per month. In recent times, however, the pace had slowed down. Already last summer a maintenance stop had to be carried out (in this case, previously scheduled) when it had not yet arrived in Sarrià. Having passed that station in the second half of last year, it has been advancing little by little until it finally became stranded about 500 meters before reaching the Mandri well.

Both at that future station and in Sarrià, work continues regardless of the stoppage of the tunnel boring machine. The Mandri well has already been finished since December, waiting for the tunnel boring machine to arrive and go through it, although this cannot be seen by neighbors and passers-by. Yes, the works on the future lobby and the emergency exit of the station are more visible, which has forced traffic on Mandri Street to be cut off and is the first thing patients see when they leave the eye surgery clinic at the station. Paseo de la Bonanova just in front of the works. In Sarrià, for its part, just over 60% of the 72 meters deep well has been excavated. It is planned that during the second half of the year the construction of the connecting gallery between the well under construction and the tunnel will begin.