Underground in New York
Norwegian scientists are key figures in the first major expansion of New York's subway system since 1930.
The ever-growing need for transport on the West Side of Manhattan is the reason why Norwegian expertise is now in action under the Big Apple. Subway Line no. 7 between Times Square and 38th St. is to be lengthened, and Norwegian scientists are currently analysing the bedrock on which this part of the city stands. The client is the New York Mteropolitan Transportation Authority.
This prestigious job went to SINTEF because our researchers can carry out what is known as “drillability testing” using very small-scale samples. No-one else in the world can do this. Such tests reveal what a given type of rock can withstand and how much resistance it will offer when a tunnel is being bored. The equipment being used on this job has been designed and built by NTNU/SINTEF.
The scientists have been carrying out tests of this sort for more than
30 years, and they have developed software that lets them model tunnel-boring
rates and costs; in combination with laboratory tests, these make up a
useful set of tools for planners. Articles on the modelling software have
been published in international journals, bringing it to the attention
of contractors and clients who have contacted the Norwegian scientists.
During the past three or four years quite a few contracts have come from
New York, and the feedback from the other side of the Atlantic has been
very positive: the laboratory is doing a god job.
Useful drilling information
Once the samples have been brought
out of the ground they are sent to SINTEF for testing and analysis. The
samples from Manhattan are tested in the laboratory in order to determine
their mechanical and mineralogical properties. After a thorough round
of data-processing they provide the scientists with valuable information
about how the tunnel should be bored. Choices of equipment and methods
are critical, since poor calculations can have major technical and financial
The drill-core job has also led to SINTEF carrying out tests for new
contracts and plans, in this case for improvements to New York’s
system of pipes and underground water-supply tunnels.
“The dimensions and length of the tunnel, its sophisticated control system, the location of the valves in special chambers and the depth of the excavations all represent highly advanced technology”, says Filip Dahl.
The work that is about to start is a matter of expanding the Tunnel no. 3 system with a new parallel tunnel, and improving the operational reliability and functioning of the whole water supply system. Doing so will reduce the pressure on the city centre’s neighbouring areas. The new tunnel will also make it possible to inspect and repair City Tunnels nos. 1 and 2 for the first time since they were built.
By Christina B. Winge
Contact: Filip Dahl