THEME TUNNEL CONSTRUCTION
PROGRESS IN TUNNEL CONSTRUCTION
I
(1) Thousands of miles of railroad tracks in the world never see daylight for they are
built in the black depth of the earth. It often takes great technical skill and ability to avoid
tunnels because of their enormous cost of construction. But there are places where a tunnel is
the only way through an obstacle. The Alps may serve as an example.
(2) For hundreds of years the peaks of these mountains had been an obstacle to
communication between European countries. In the middle of the 19th century, constantly
expanding railways made the French and Italian Governments seek for a direct connection.
The experts spoke in favour of tunnelling. A tunnel eight miles through the Alps? Some people
had doubts, but some dared to do it.
(3) Boring the Mont Cenis tunnel, the Alpine pioneer, was an extremely hard job. With
only hand tools employed, the advance was very slow. Had the construction continued at the
initial rate, it might have taken 75 years to complete the tunnel! However, with compressed-
air drills and dynamite introduced, the progress was accelerated. In 1870 the news flashed
through Europe that the Alps had been conquered at last. But the tunnellers may have
encountered some more difficulties with the tunnel since it was only in 1871 that the Mont
Cenis tunnel was opened fo'r traffic.
(4) The success of the Mont Cenis tunnel started a wave of Alpine tunnels, the St.
Gotthard and Simplon tunnels being the most remarkable among them. The story of their
construction is the story of constant struggle of tunnellers against the powerful,,foj;ces^of
nature. Very often hidden mountain streams of extremely hot water rushed into the-
workings. Rock dust and fumes from oil lamps and explosives filled the hot steamy air
poisoning the workers. There is no need to say that a special ventilation system ought to have
been used. Unfortunately, the ventilation methods being unknown at that time, the death-
rate among the tunnellers was extremely great.
(5) In spite of all difficulties the workers and engineers completed their task
successfully.
(6) Another tunnel of some interest up to our time is the tunnel under the river Thames.
By present standards this tunnel may be said to be a very archaic structure, but it is still in use
as part of the London underground railway system because it was a pioneer of construction in
the modern manner. While building this tunnel Mark Brunnel, a celebrated engineer, worked
out the idea of using a shield
2
to lead the excavation.
(7) If you happened to travel by London Underground you must have read the
following words on the wall of one of the stations: "This tunnel which runs under the Thames
from this station was the first tunnel ever driven beneath the river. It was designed by Sir Mark
Istambul Brunnel and completed in 1843."
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