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Cairo metro reaches TBM milestone 26 Jun 2013
Patrick Reynolds for TunnelTalk
Tunnelling on the second phase of Cairo metro Line 3 (Al Thawra) is completed with planning under way for procurement of the next phase of construction.

NFM EPBM relaunched for 680m drive to Haround el Rashied site
(Photo: NAT)

As part of a Phase 2 contract extension announced in February, a 9.46m diameter NFM EPBM relaunched from Al Ahram Station on a 680m drive to Haroun el Rashied, completing the bore at the end of May. The metro line is a single bore, twin-track tube.
Civil engineering works for Haroun el Rashied Station are included in the €40 million extension package awarded to the main contractor on Phase 2 - a Vinci-led consortium comprising Bouygues, Orascom and Arab Contractors (VBOAC). It was decided to complete tunnelling as soon as the station's diaphragm walls had been finished rather than wait for the entire box to be excavated.
Including the extension package, Phase 2 of Line 3 comprises 7.1km of tunnel, seven inter-station access shafts and five stations: Cairo Fair, Stadium, Kolyet El Banat, Al Ahram and Haroun el Rashied. By early 2014 the line will be operational up to Al Ahram Station, taking the total operational length of Line 3 to 10km and nine stations. While Haroun el Rashied will be structually completed it will not be fitted out and commissioned until later.

First breakthrough at Stadium station (Photo: NAT)

Geology along the alignment of Phase 2 comprised sands with stiff clay layers and some cobbles. Tunnel depth ranges between 12m and 30m.
The EPBM was initially launched at Cairo Fair Station to drive east. Initial teething problems resulted in cutterhead modification and replacement of some discs with rippers, said the client, Egypt National Authority for Tunnels (NAT). Average progress has been 15m/day over its last three drives.
Another TBM, a 9.4m diameter Herrenknecht Mixshield, was used for the 1.9km-long westbound drive from Cairo Fair to join the tunnel to the Phase 1 section of Line 3, at Abbasia interchange station. The bentonite slurry shield was introduced to the contract during Phase 1 when it took over, and completed, the last short stretch of tunnel after the original machine was buried in a collapse.
Plans for the third phase of Line 3 envisage an extension of almost 18km, with 15 stations, which will run below the River Nile to the west of the capital. Almost 14km of this is to be bored tunnel, and eight of the stations will be underground.

Cairo metro alignment

Work is also under way on planning the fourth and final phase of Line 3, as well as Phase 1 of Line 4, said NAT. The client hopes to let both projects in the near future. Haroun el Rashied Station is being constructed early to give the JV contractor a location to extract underground equipment.
NAT has been supported on development of Cairo metro by consultants Systra, ACE and EHAP.
The €235 million five-station first phase of Line 3, completed by VBOAC, came into service almost 18 months ago. The 4.2km-long section took 51 months to complete.
Metro development in Cairo saw Line 1 built and brought into service in the 1980s, and Line 2 developed in five phases between 1996-2005. Only 5km of the 44km-long Line 1 is underground. The majority of Line 2, however, is underground - 12 out of 18 stations along the 19km-long route are below ground.
References
Symptoms of the collapse syndrome - TunnelTalk, July 2010
Convertible EPBM heading for Cairo Metro - TunnelTalk, September 2009
Cairo Metro tunnel collapse - TunnelTalk, September 2009

           

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