AJV led by Vinci Construction Grands Projets has won a contract worth US$325M for the civils work on the first phase of Line 3 of Cairo’s metro, involving 3.5km of single bore tunnel.
Tunnelling work on the east-west line is due to start around March 2008 and complete early 2009. Excavations will also see 1.3km of cut and cover tunnel plus five underground stations totalling 875m in open cut length.
A refurbished, 9.5m diameter Herrenknecht slurry TBM will drive the tunnel at depths of 20m-30m from Abbasia to Attaba, with 13 breakthroughs and relaunches at the cut and cover sections. The finished inner diameter will be 8.35m. The slurry TBM was previously used in phases 1A and 1B on the JV’s Line 2 contract.
Geology along the route consists of surface backfill along with alluvial deposits, including sand, clay and gravel. Groundwater levels vary from 7m below surface at the start of the drive, in the east, to less than 2m down in the west, at Attaba.
The cut and cover sections of tunnel will be 10m wide and around 25m in depth. The box stations will be around 25m wide and vary in depth from 22m at Abbasia to 32m at Attaba. Excavation works including diaphragm walls and ground treatment is expected to take around six months at each of the five stations – Abbasia, Abdo Pasha, El Gueish, Bab El Shaaria and Attaba.
Phase 1 is due to start construction by June to finish mid-2011. Vinci’s JV partners are Arab Contractors, Bouygues and Orascom Construction Industries.
