Contractors working on one of the Doha Metro’s flagship stations celebrated a milestone in the project after one of its Tunnel Boring Machines (TBMs) broke through the air after digging out 1.6km 2.3km underground.

The Al Mayeda TBM could be seen emerging at Msheireb Station yesterday, marking the first “breakthrough” in the complex tunneling works for this hub, Qatar Rail said.

It is one of 21 TBMs currently being deployed to dig out a total of 113km of tunnels under central Doha by 2017.

So far, the specialized machines have completed 30km of the tunneling, which accounts for more than a quarter of the necessary excavation works, Qatar Rail added in a statement.

In an update in April this year, the rail organization said 18.5km (about 20 percent) of the tunnels had been dug out to create Qatar’s new public transportation system.

The journey of the Al Mayeda TBM has not been without issues since it was launched at Al Corniche station in November last year.

Just a few hundred meters from its destination, the TBM hit an unexpected, underground water source, which delayed its works for several days while engineers resolved the issue, QR said.

Now that it has finished its first job, Al Mayeda will be transported by road to Al Qassar station, between West Bay and Katara Cultural Village  to Corniche Station to start digging out the section of the Red Line towards Doha Exhibition Center.

Damaged machine

This is at least the second incident faced by a TBM during the complicated excavation process to create the tunnels for what will be four lines running underneath as well as above-ground across Qatar.

In February, the TBM known as “Al Bidda” became damaged after part of one of the twin tunnels on the Red Line North flooded in what Qatar Rail described as a “gate closure failure” during pilot tunneling.

Pilot tunnels are typically small-diameter holes bored in advance of, or parallel to, the main tunnel that are used to gather detailed information about the underground soil, sand and rock conditions.

Engineers had to pump water out of the tunnel, then installed “dewatering” wells to get rid of excess surface water.

The Al Bidda TBM was later recovered, cleaned and repaired in three months – a process that would usually take six to 18 months, Qatar Rail added in a statement to Doha News about the incident.

Speaking to Doha News in April about the incident, Qatar Rail CEO Saad Ahmed Al Muhannadi said the flooding incident had not affected the timeline of the metro project because work had been operating five months ahead of schedule on the line at the time of the flooding.

Msheireb Station progress

In its latest update, Qatar Rail said construction at the Msheireb station is scheduled to be completed by 2018. The first phase of the public transportation system is expected to open to passenger traffic by late 2019.

Several other TBMS are to be deployed to dig out the tunnels to connect to the Msheireb site.

Work includes excavating an area of land equivalent to the size of five football pitches some 40m underground in order to construct the station.

So far, some 800,000 cubic meters of soil has been removed  – weighing the same as half-a-million Toyota LandCruisers, according to Qatar Rail.

It has taken some 70,000 truck journeys to haul away the excavated soil at the station site, some of which will be used in the construction of Qatar’s long-distance passenger and freight line, which is scheduled to enter operations by 2018.

Chris Haskell, senior project manager of the Msheireb Station, highlighted the scale of the project:

“If all the trucks were lined up, the queue would stretch from Doha to Mecca. Each day, we de-water the equivalent of an Olympic-sized swimming pool.”

Two stages

Doha’s Metro system will be constructed in two phases, and will play a crucial role in trying to alleviate congestion on the city’s roads, as well as moving large numbers of football fans around the country during the 2022 World Cup.

Phase one of the public transit project involves the construction of 37 stations on four lines:

• The Red Line North, running from a connection with Lusail’s light-rail line to Msheireb via West Bay;
• The Red Line South, running from Msheireb to Mesaieed, with a branch to Hamad International Airport;
• The Green Line, running from Al Rayyan Stadium to Msheireb via Education City; and
• The Gold Line, running from Villaggio Mall to the area around the old Doha International Airport, via Msheireb.

In the second phase, a further 70 stations are expected to be added to the network as existing lines are extended further out of Doha, a parallel Gold line is built west of Msheireb and a semi-circular Blue Line is created.

This is expected to loop from West Bay through Al Sadd and towards the airport on a route that appears to roughly follow C-Ring Rd. Completion of phase two is currently set for 2026.

Thoughts?

This article was edited to correctly reflect the length of tunnel excavated and the name of the station where the TBM will start the next phase of digging out, both of which were mis-stated in a media release.