The Civil Engineering Contractor August 2018 | Page 29

TECHNOLOGY
simultaneously tunnelled their way
forward to construct 2.5km a week of
metro tunnels beneath Doha. This parallel
performance has gained the project a place
in the Guinness Book of Records.
The demands on each TBM are
complex due to the dense urban
development; for example, near the
imposing beach promenade Corniche;
under high-rise neighbourhoods; as
well as hotel-rich tourist centres. A
key requirement therefore was to avoid
earth settlement during construction.
The proposed inauguration of Doha
Metro phase one from Al Qassar to Al
Wakrah is 31 October 2018.
The future: freeways
underground
areas in a city you would need to do this
at scale.
But could underground infrastructure
be the answer to many of humankind’s
urbanisation problems? nn
“The rule of thumb in engineering
is that the ratio of constructing
on ground is R1 compared to
R10 for elevation above the
ground and R100 for below
ground. From a cost point of
view, building underground would
always then be the last option in
infrastructure.”
Jack van der Merwe, CEO of Gautrain
Management Agency.
South African-born and bred billionaire
entrepreneur Elon Musk is pitching
that his The Boring Co. can build
transportation-orientated tunnels faster
and cheaper than current technology can.
The company is currently experimenting
below its offices in Los Angeles to design
machines capable of drastically reducing
the cost of tunnelling by, for example,
drilling tunnels at about half the diameter
of those for subways.
Musk talks of constructing a vast
network of criss-crossing tunnels below
cities like Los Angeles, in which cars
and people will be hurtled across town
on electrically driven car-carrying
platforms at speeds of 200km/h.
Elevators would bring cars, cargo, and
other vehicles up and down from the
surface to tunnels that would consist of
a system of tubes on what Boring calls
an ‘electric skate’, bypassing all traffic
above ground. Cutting tunnel-boring
costs dramatically won’t be easy, until
Musk’s underground electric transport
vehicles resolve a bunch of engineering
challenges, such as reliability and safety
of the elevator, loading and unloading
times, and the number of dedicated
Robin Jackson, director of DDE, shows such of the equipment that is used in a half-
automated half-labour methodology.
References
http://www.govtech.com/fs/infrastructure/taking-a-look-below-a-smart-city.html
https://www.moneyweb.co.za/news/south-africa/gautrain-new-tunnel-solve-excess-water-drainage
https://www.thepeninsulaqatar.com/article/05/04/2018/Qatar-Rail-completes-77-work-of-Doha-Metro-Project
CEC August 2018 - 27