Cairo is intensively expanding its metro network with construction currently moving ahead on Line 3 to the second phase and soon the third, while planning is being advanced for the later stages to extend both further east and west. A major addition to the existing network, Line 3 will be 40.3km long with 32 stations and still further lines have been on the drawing board for some years and are in studies – for Lines, 4, 5 and 6.

The present focus of work on Line 3 is in central Cairo, on the east bank of the River Nile, where tunnelling has been underway for approaching three years. The tunnelling works on Phase 1 have reached the closing stage on the first phase, which includes recovery of a stuck TBM through a rescue shaft using ground-freezing and the use of an additional TBM brought in to complete the workload.

Next door, to the east, early activities on Phase 2 of the line’s development are progressing well with a further TBM onsite and being prepared for launched in early 2011.

Contractor for both the Phase 1 and 2 of Line 3 is the French-Egyptian consortium of Vinci Construction Grands Projets, Arab Contractors, Bouygues and Orascom Constructio Industries. The JV was awarded the contract for Phase 1 in 2007 by the National Authority for Tunnels (NAT), which is part of the Ministry of Transportation and the second phase was won in mid-2009.

French consultant Systra has undertaken a variety of services to the Line 3 works, from feasibility studies to the tender phase. The services range from design feasibility, general features and preliminary design with local subcontractors providing the basic design and technical tender documents, including the bills of quantities and specifications.

While tunnelling completes on Phase 1 and gets set to start on Phase 2, Systra is developing the design and tender documentation of the initial stages of Phase 3 to be ready this year, and studies are underway for Phase 4.

Line 3
In layout, Line 3 is like a giant Y-shape lying on its side across Cairo, the branches being on the west bank of the river. Once completed, the line will run from the international airport in the east and then westwards through the city and below the Nile to the west bank, where it will split with branches north and south to Imbaba and Mohandessin, respectively.

Line 3 is a single bore, twin-track tunnel of 8.35m i.d., and the concrete rings (5 + 2 counter) have 400mm thick segments to give an outside diameter of 9.15m.

Geology along the alignment comprises sand that is medium dense to dense, with clay pockets in the upper layers. The groundwater is level is slightly below street level in the downtown area and lower further east. The tunnelling on the project will use a combination of slurry and EPB TBMs.

Phase 1
Phases 1 and 2 will construct much of the main stem of the Y-shape of Line 3. They have a combined length of 11.4km with a total of 10 stations, and cover the business district, or downtown Cairo, out to the edge of Heliopolis, halfway to the airport.

Phase 1 is a little over 4.2km long with five stations, which are from west to east – Attaba, Bab El Shaaria, El Geish, Abdou Pasha and Abbasia. The line will have its first interchange station, at Attaba, with Line 2. Construction involved both TBM and cut and cover works.

Phase 2
The second phase is 7.2km long and also has five stations – four originally planned and a fifth added for the contractor to have an exit shaft for construction reasons.

Running east from Abbasia, the original stations are Cairo Fair, Stadium, Kolyet El Banat and Al Ahram. The additional station is Haroun, originally to be part of Phase 4, but the change now means Phase 2 ends a little nearer Heliopolis.

Phase 3
Phase 3 is to be constructed in three stages – 3A, 3B and 3C – with a total of 15 stations over 17.7km of line, and two crossings of the Nile via the island of Zamalek.

The first stage, 3A, will be 4km long and start to extend the line to the west from Attaba (built in Phase 1), and the initial drive will cross Line 1 where an interchange station will be built at Nasser. From there, the line will pass under the Nile with a further three stations in the area (Maspero, Zamalek and Kit-Kat Square).

Stage 3B is to be 6.6km long with six stations and will take the line onto its north branch after first constructing the Sudan station, which will be where Line 3 will split and so will have a stub tunnel for the south branch to be constructed. The north branch includes stations at Imbaba Airport, Monira, El Wehda, Ring Road and it terminates at Rod El Farag Corridor. A workshop area for the trains and infrastructure maintenance will be constructed between the last two stations.

With five stations over a stretch of 7.1km, stage 3C will take Line 3 onto its south branch from the previously built junction station at Sudan and then the line will terminate at an interchange to Line 2, at Cairo University. There will be four intermediate stations built along the south branch, and proceeding south they are – Tawfikia, Wad El Nile, Gamat El Dowal El Arabia and Boulak El Dakrour.

An underground diversion structure is to be built that will allow the two branches to be operated with no grade intersections of the railtracks.

Design work on Phase 3 is due to be completed early in 2011, says Systra.

Phase 4
Phase 4 of the line’s development is at the opposite end, in the east, extending out from the end of Phase 2 works towards the international airport. Prior to the adjustment with Haroun station to help the Phase 2 works complete using an exit shaft, the plan for Phase 4 specified the works would be done in two stages – 4A and 4B – with eight stations over 11.3km. The total would be adjusted to seven, depending on what may remain to be done at Haroun; the change would also see the number of stations in stage 4A down from five to four. The total distance to be constructed may also be reduced slightly.

The listed, unadjusted plan for stage 4A states that over a 6.4km length it would have five stations, and proceeding eastwards they are – Haroun, Heliopolis Square, Alf-Maskan, Al Arab and Ain Shams 1.

Stage 4B would have three stations over a distance of 4.9km, taking Line 3 via stations at Ain Shams 2 and Omar Ibn El Khatab out to the international airport, where the line terminates.

Construction – Phase 1
Tunnelling work on Phase 1 has been undertaken using slurry TBM excavation. The groundwater level is 1m-2m below street level in the downtown area.

A 9.4m diameter, refurbished Herrenknecht slurry TBM, christened Cleopatra, was launched at Abbasia to drive westwards toward Attaba. The machine was previously used on construction of Line 2, on stages 1A and 1B of Phase 1 of that project.

Excavation began in the first quarter of 2008 and was originally expected to complete in the early part of 2010. However, in September 2009 the works suffered a major setback when a collapse buried the TBM in the stretch between El Geish and Bab El Shaaria stations.

The TBM had constructed the majority of the tunnel for Phase 1 when there was an inflow of water laden gravels and sands under a 20m head. The funnelling into the tunnel did not cease until the ground disturbance reached up to the surface, creating a sinkhole at a road. The tunnel alignment in this section of the project mainly follows the roads.

Fortunately, no-one on the surface or in the tunnel works was hurt by the accident, which is suspected to have resulted from two segments of the lining being misplaced in an erected ring, and subsequently collapsing into the tunnel with the consequent inrush. A cut-off wall was built back along the tunnel and from there to the TBM the tube was flooded to help ensure stability and prevent any further problems.

A recovery operation was launched for the buried machine, and work involved sinking a shaft in front of the collapsed area with walls constructed to a depth of more than 90m to penetrate, and gain the beneficial base seal, of a clay layer. The shaft was built by Bauer. Works then proceeded to install a ground-freezing system using arrays of injection pipes and brine solution, and the recovery is close to completion.

A new Herrenknecht bentonite slurry TBM was sourced to complete the tunnelling work on Phase 1 while the recovery operation was being executed. The new machine was launched in July 2010 and bored eastward towards the rescue shaft where it will hole through and be removed, expected around the end 2010.

By the end of 2010 the tunnelling works had completed 3.35km of TBM excavation and 1.1km of cut and cover, says Systra. Overall, it notes, the construction programme for Phase 1 has suffered on slight delays due to the tunnel collapse.

Construction – Phase 2
For the first 2km, or just over half, of Phase 2 – east of Abbasia and en route to Cairo Fair – the geology lies within the Nile alluvial valley. Groundwater is slightly deeper in Phase 2 than in Phase 1.

The Vinci-led JV plans to use the slurry TBM that was brought-in to complete Phase 1 on this portion of the tunnel. The TBM will break out at Cairo Fair.

The remaining 1.85km of the Phase 2 tunnelling work will be undertaken by a 9.46m diameter EPBM manufactured by NFM Technologies, which arrived on site for assembly early in the fourth quarter of 2010 and is due to start driving early in 2011. Geology along that section includes clay, sand and sandstone. The contractor requested that the machine will be capable of being adapted to slurry mode for possible later use in the project.

The EPBM will be sued to construct the tunnel between Cairo Fair and Haroun (now added to the Phase 2 works, as previously noted). The extra distance to be built that will take the tube to Haroun will be used during the operational phase of the metro line as a temporary sidings area, notes Systra.

Civil works for Phase 2 are to be completed in 2012, says Systra. The plan has been for this phase of Line 3 to come into service by about late 2013.

Preparations – Phases 3 and 4
Systra is currently focused on the basic design with tender documentation for stage 3A of Phase 3, and documents for 3B and 3C are expected around March 2011, which would complete planning for that section of the project. The early work on Phase 3, including feasibility studies and general features, began in 2002. Site investigations have been completed.

It is anticipated that the second Herrenknecht slurry TBM on the project – used to complete Phase 1 and is excavating part of Phase 2 – could be held for tunnelling works on Phase 3A of Line 3, between Attaba and Kit-Kat Square. Slurry TBM drives are also planned for the other two stages of Phase 3, to construct the north and south branches.

Civil works for Phase 3 are to be completed in 2015, says Systra.

The feasibility study for Phase 4 was undertaken almost a decade ago, and the necessary site investigation works are being planned. The expected tunneling method for Phase 4 is to use EPB TBMs.

Current studies for stage 4A of Phase 4 are underway, led by Systra’s project manager for Phase 4, Paolo Patrizi, and are expected to be completed by the end of 2011. The detailed studies for stage 4B have yet to begin. The completion schedule for civil works on Phase 4 has yet to be determined.

Key challenges or further works include limited areas in the dense urban environment to help station construction, which could see studies to explore possibilities for mined tunnelling being used, says Systra


Cairo’s extensive metro strategy for six lines is currently focused on construction of Line 3 Line 3 will be constructed in four phases, and Phase 2 tunnelling is about to start Construction of Phase 1 of Line 3 was completed by the end of 2010 A rescue shaft was used to recover a TBM trapped by a collapse on Preparations for ground-freezing underway at the bottom to the rescue shaft Reaching the buried TBM from the rescue shaft; The recovery works advance at the TBM