In early February, NFM Technologies, part of the Wirth Group, claimed a new world record for the advance rate of its 11.95m diameter TBM working on Section IVa of the 42km long Line 9 for the Barcelona metro (T&TI, February, p26).
The dual-mode EPBM, “Bessi”, excavated an impressive 39m in a single day, whilst concurrently installing 22 segmental rings. At the time, the machine was operating in open mode on a section that included 270m radius curves.
To date, Bessi has completed over 70% of its 4,269m tunnel since its launch in June 2003. Current plans call for the TBM to finish the drive and be dismantled by June this year, in preparation for a further 8km drive from the Zona Universitaria to Sagera stations.
Commending the performance given the tight radius of the curves for a machine of this size, NFM praised the site team led by UTE Linea 9 JV and the TBM.
Less celebratory was the news that on 27 January a sinkhole associated with tunnel works for Barcelona’s Line 5 extension caused the collapse of buildings and the evacuation of 1,000 people. Two blocks of flats had to be demolished due to damage caused by the sinkhole 20m wide and roughly 30m deep.
Details of the cause of the collapse are not yet available, although initial reports blamed a sandstone fault.
The Catalan Minister for Territorial Policy and Public Works said he attributed the tunnel problems to the technical specialists involved in the project. Independent geologists commissioned to report on the collapse by the residents are said to have been denied access to the site, with safety concerns being cited as the reason.
Despite this, a judge has opened an official investigation to determine who was responsible for the collapse. The state run agency in charge of the extension, GISA, together with contractors FCC, Comsa and Copisa Constructora Pirenaica, management company TEC-4 and geological surveyor Geocontrol will all be investigated, together with the regional Catalan government.
