China has succeeded in solving a series of technical problems in
building the Qinghai-Tibet railway, the highest railway in the
world.
Chinese railway builders and scientists have developed effective
ways, based on experimentation and experience in constructing the
railway in the past year, to treat major problems like highland
cold, water and oxygen shortages, and frozen earth.
The 1,118-km (695 miles) railway will extend from Lhasa, capital of
the
Tibet Autonomous Region in southwest China, to Golmud in Qinghai
Province in the northwest.
More than 960 kilometers (597 miles), or over four-fifths, of the
railway will be built at an altitude of more than 4,000 meters
(13,123 feet) and 547 kilometers (340 miles), or more than half of
its total length, will be laid onlong-frozen earth.
To
guarantee the stability of the railroad bed and the safe operation
of the railway, scientists and builders have tried to avoid laying
rails in areas with severely frozen earth, and built bridges over
some areas where the frozen earth is unstable, or ventilation dykes
and paved layers to preserve the frozen earth.
A
research report by the Xibei (northwest) Science Research Institute
under the China Railway Engineering Corporation shows that
thermosiphons are expected to help resolve problems resulted from
the frozen earth.
The report said experiments showed the use of thermosiphons to cool
the railway bed was feasible.
Experts explained that thermosiphons transmit heat in one
direction, which means heat will be transmitted from underground to
the surface, but cannot be transmitted from the surface to below
ground.
Wide use of thermosiphons could help preserve the frozen earth,they
said.
Chinese scientists started research on the frozen earth as early as
since the early 1960s.
Experiments involving new technologies, techniques and materials
are going well in five frozen earth areas along the railroad.
Meanwhile, breakthroughs have been made in solving shortages of
oxygen and water.
No
deaths caused by pulmonary edema and cerebral edema, the aftermath
of oxygen shortage at altitude, have been reported on the
construction site since the railway project was launched one year
ago.
China has been considering building the Qinghai-Tibet railway for
more than five decades. Rapid economic growth and technological
advances over the past two decades have made the project
possible.
Upon completion in six years, the railway will end a history of the
Tibet Autonomous Region being inaccessible by train.
(
July 13, 2002)