Final breakthrough into the shaft north of Legtaifiya Station completes TBM tunnelling on the 11.8km-long underground section of the 15km Doha Metro Red Line North in Qatar.
The last of four owner-procured TBMs completed the sixteenth and final Red Line North drive on 20 March (2016). Just eight days earlier (12 March) the Salini-Impregilo/ SK Engineering/ Galfar Al Misnad (ISG) joint venture contractor completed the parallel drive. The achievement marks successful excavation of the first of the running tunnels for Phase I of Doha’s brand new metro system, which is being built ahead of Qatar hosting of the Soccer World Cup in 2022.
Excavation of the Red Line North began in July 2014. The best daily rate achieved was 42m in July last year (2015), with a best combined daily progress rate for all four machines of 114m (February 2015).
Abdulla Al Subaie, Managing Director of QRail, said: “We are particularly delighted by the progress on this section of the project as we and our colleagues at ISG have had to overcome some significant challenges. It is well known that one of our TBMs suffered damage during an inundation event about a year ago and the achievement today shows how effective our recovery operations were and that overall project progress was not affected.”
Al Subaie added: “Across the project as a whole we are continuing to move to plan. Later this year we will be over halfway to delivering the whole project and tunnelling operations are expected to finish in the Autumn. At that point, we move from construction into systems installation as track, power supply and signalling start to be installed. We also start the architectural finishes of the stations.”
TBMs are still in the ground on Phase I construction of the underground sections of the three other major Doha Metro construction contracts – the 12km-long underground section of the 25km-long Red Line South out to Hamad International Airport and Al-Wakra, held by the Qatari Diar/ Vinci/ GS Engineering/ Al-Darwish JV; the 16.6km underground section of the 22km Green Line, held by the Porr/ Saudi Binladen/ HBK JV; and the all-underground 13.3km Gold Line, held by the Greek and Turkish Yapi Merkezi/ SFTA/ Aktor JV.
Project owner QRail this week reports that 85% of the total of 53.7km of twin-running alignment across all four contracts is now complete, for an overall project completion of 37%. The 37 cut and cover stations that are included as part of the respective tunnelling contracts are all under construction, with 17 now at the stage where the concrete roof slab is being cast. The central hub station at Msheireb – where all four lines intersect – is being constructed under a separate construction contract.
A total of 21 EPBMs, all of them manufactured by Herrenknecht of Germany, were procured for delivery of the four Phase I tunnelling contracts – four machines for the Red Line North, five for the Red Line South, six for the Green Line and six for the Gold Line. Simultaneous excavation by all 21 machines in September last year (2015) has been officially verified as a Guinness World Record for the number of TBMs excavating at a single moment in time on the same project. The machines for the Doha Metro are all approximately 7.7m in diameter.
Three of the six EPBMs excavating the underground section of the Green Line between Riffa in the west of the city, and Mansoura in the east, have already been decommissioned after achieving final breakthroughs last month (February 2016). The remaining three machines that are in the ground are expected to complete all tunnelling on the Green Line next month (April 2016).
QRail Project Director Jassim Al Ansari said: “We are continuing to make good progress against our challenging objectives. To date 30km out of 33km has been tunnelled on the Green Line, a remarkable feat considering we began tunnelling on this line less than 18 months ago."
Progress on the Gold Line is less well advanced, largely because the contract was awarded a year later than for the other three lines, in May 2014. Progress on the Red Line South – which was expected to be significantly more difficult as a result of the high groundwater levels at the airport near the coast – is nearing completion.