Seli Overseas achieves milestone success on its section of the Doha Metro Gold Line, ahead of schedule, with breakthrough of the 7.2m diameter Herrenknecht EPBM into Al Aziziyah station.
Seli Overseas Regional Manager Michele Sposetti told TunnelTalk that the TBM was launched in early July 2015 on a 4.2km-long drive from Al Soudan station, breaking through at Al Aziziyah station on the western end of the line on 1 May – 51 days ahead of schedule.
During the drive through geology that included flints and limestone with karstic voids and groundwater, progress rates averaged 18m/day, peaking at 43m/day. The best calendar month was January, said Sposetti, during which 620m of production was recorded; the best 31-day period achieved was 920m between 19 January and 18 February.
The tunnel alignment of the section of Gold Line in the west of the city passes below a low-rise urban area at a steady 14m below the surface. The groundwater level is near the surface.
The east-west running Gold Line in the capital of the Arab Emirate of Qatar is being developed by Qatar Rail.
Seli Overseas’ local subsidiary, Seli Middle East, performed the tunnelling work under subcontract to the Alysj JV (comprising Aktor, L&T, Yapi Merkezi, SFTA and Al Jaber) on Lot 2.3a.
The company’s Qatar-based subsidiary provided the TBM crew, site personnel, TBM spare parts, cutters and consumables for the machine, and inputted to the design of TBM-related equipment, ancillaries, specification and site layouts, and at tender phase with tunnel-related costs.
The TBM was acquired by the Alysj JV along with a total of five others from Herrenknecht for the Gold Line works so far. The main contractor’s consultant on the scheme is Atkins.
“We started last but finished first,” Sposetti told TunnelTalk.
Phase 1 of the Gold Line is a total of 16km long with 13 box stations below ground. The tunnel lining erected by TBMs between stations comprises 330mm thick precast concrete fibre-reinforced segments assembled in rings (6+1) of 1.5m length.
Seli Overseas is owned by Italian construction major Grandi Lavori Fincosit SpA (GLF).