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Greater
Cairo Metro Network
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Line
1
Line
1 forms the backbone of the Metro network in Cairo as it
passes through the most important residential and business
districts of the city. The line was formed by connecting the
existing railway line from Helwan in the South to the existing
railway line to Marg in the North East by means of a new
underground line beneath the central business district of Cairo.
The Total length of the line is 44 Km including 34 stations.
The length of the underground section is 4.5 Km including 5
underground stations. The Project commenced in 1982 and ended
completely in 1989.
Line
1 was designed to carry 60,000 passengers per hour in each
direction, in electrically powered trains comprising 9 cars each,
with a headway of 2.5 minutes and a maximum speed of 100 Km/hr and
a track gauge of 1.435 m.
Construction
Method:
Diaphragm
Walls were used to support the sides of the excavation during the
phases of construction and became part of the structure by being
joined to the raft and roof , thus forming the cross-section of
the tunnel and stations. Precast walls were usually used in the
tunnel section and cast in-situ walls were used in the stations.
Trenching for the walls was done using cement/bentonite slurry for
the precast walls and bentonite slurry for the cast in-situ walls.
A grouted plug was used between the diaphragm walls at their toes.
The grout consists of cement/bentonite followed by soft silica
gel. The function of the plug was to reduce the permeability of
the soil to permit dewatering of the excavation with limited
discharge and without affecting the level of the groundwater
outside the walls to ensure the stability of the adjacent
buildings. The precast panels in the tunnel sections were 0.45 x
2.5 m with 12 m length. The cast in-situ walls thickness varies
between 0.6 to 1.0 m depending on depth.
Line
2
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Unlike
Line 1, Line 2 is a wholly new line. The Line
extends from Shubra-El-Kheima station to Om-Elmasreen Station with
a total length of 19 m and 18 stations. The Line is currently
extended to Monib Station. Line 2 provides interchanges with Line
1 at Mubarak and Sadat stations. It also provides interchanges
with the Egyptian Railways at Shubra-El-Kheima, Mubarak and
Giza Stations. The Line includes 6 Km of at-grade and viaduct
section with 6 at-grade stations, cut and cover tunnels of length
1.8 Km, bored tunnel of length 9.5 Km and 10 new underground
stations besides the development of the two interchanging stations
at Mubarak and Sadat Stations. Line 2 was completely finished on
October 2000.
For
the bored tunnel section, a single tunnel 8.35 m in internal
diameter was constructed using two Herenknecht bentonite slurry
shield TBMs, each 9.43 m in diameter. The tunnel has a bolted
precast concrete segmental lining, each 1.5 m wide and 0.40 m
thick. It should be noted that it was the first time that the
River Nile was crosses by a bored tunnel underneath the bed of its
two branches.
The
underground stations are typically 150 m long, 21 m wide and 23 m
depth, each having three levels. They have been built using top
bottom construction between diaphragm walls 1.2 m thick and
extending down to 55 m below ground level. The water table was
about 2 m below the ground level. Soil injection was used to form
a low permeability plug, 7 m in thickness, at the base of the
walls.
The
trains have a design maximum speed of 80 Km/hr with a minimum
headway of 105 seconds, transporting about 1.2 million passengers
per day. |
