Herrenknecht built, supplied and helped operate 21 of the TBMs, shifting more than four million metric metres of material including limestone, shale and dolomite from the ground.
For the world’s swelling cities, transporting their many habitants poses a challenge that continues to grow in complexity. A city’s success hinges on the fluid movement of people. The implementation of an effective transport strategy can ease congestion – good for both the economy and the environment,
Now, in the first part of a new SmartRail World feature series, Work in Progress, Dave Songer gives readers a window into some of the world’s most innovative and inspiring technological and engineering projects currently underway. Each month we focus on a different aspect, from building and master planning through to passenger safety and fare collection. This week is the turn of the Doha Metro, which undertook a huge tunnelling effort to carve out 37 stations for the network that when phase two is complete in 2026 will comprise 100 stations.
The road network is no longer a viable option to carry the millions who need to get from A to B, promoting cities that rely on tarmac for transport to take extreme action. Hanoi in Vietnam, a city with a population of seven million people that use a staggering five million motorbikes, is planning to banish all those bikes from its roads by 2030, citing environmental and congestion concerns. But there is cause for optimism. Cities of all sizes are taking steps to avert the problems posed by ineffective transport, recognising that a modern, fast and efficient network that works for the people who use it can pay dividends.
.A world first.
With around 70 miles of underground tunnels dug over 26 months, the Qatari capital’s inaugural metro registered a world record – running 20 tunnel boring machines (TBM) at the same time. Ahead of Doha Metro's first planned first journey in 2019, Herrenknecht built, supplied and helped operate 21 TBMs for the tunnelling, shifting more than four million metric metres of material including limestone and shale from the ground.
"Qatar’s vision is to connect every corner of the country by public transport," says Dr Martin Demmler, senior director of the Qatar Integrated Railway Project, adding that managing 21 TBMs beneath a metropolis like Doha is only possible with 100% commitment from all partners involved.
The German company, which also competed tunnelling for London’s Crossrail, carried out excavation works on three of Doha Metro’s four lines: Red Line North, Green Line and Gold Line at a rate of 1.5 miles a week. It was unchartered territory for the Gulf state, with no tunnelling of any sort in Doha before the first spade went in the ground.
The total absence of tunnelling in the city – that in 2022 will host the football World Cup – gave it a real advantage over other tunnelling projects that have taken place in other parts of the world, due to the fact they have to navigate their way around pre-existing infrastructure. For London’s Crossrail, space was at such a premium for the installation of the new Tottenham Court station that the new line had to go over part of the Northern line Underground network and under an escalator – giving just a metre of clearance.
Sealed from within.
Strengthening the tunnels after they have been dug is an absolutely vital aspect of the tunnelling and one that sets Herrenknecht’s TBMs apart from the competition. Immediately after the Herrenknecht TBM excavates, the near-1,000-tonne contraption slots 70,000 individual concrete lining segments – each weighing 3.4 tonnes – into place, sealing the tunnel from water ingress and strengthening it for the life of the network.
Ensuring its machines kept moving to meet its tight target, Herrenknecht established a full-service centre in Doha to provide additional support that presented proactive personnel fully trained in tunnelling technology, assembly and disassembly and spare and wear parts management.
"The world has never seen such performance. What Qatar Rail and our contractors in Doha have accomplished in just 26 months of construction time with the highest standards of performance,” says Dr. Martin Herrenknecht, from the company’s chairman of the board of management.
The next Work in Progress is due to be published on Thursday 9 November. If you would like to suggest a project, please contact email@example.com
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