Tunnelling work at the Nehru Park Metro Rail site has
been progressing well despite challenging soil conditions, officials of
Chennai Metro Rail Limited (CMRL) said.
With two
tunnel boring machines (TBMs) from China shipped to the country in
December, 2011 — as part of an agreement between CMRL, joint venture
partners Larsen and Toubro and Shanghai Urban Construction Group — this
site was the first to begin tunnelling work in July 2012.
At present Metro Rail uses 11 TBMs at various sites across the city.
The machines tunnel passages that will eventually connect underground
stations.
The first TBM at the Nehru Park site that
began tunnelling in July has completed 565 metres and the second one,
which started in October, has drilled 455 metres. The two machines still
have 939 metres to tunnel through from Nehru Park station to Egmore
station, a CMRL official said.
“We have finished
construction of the diaphragm walls of the station. Platform work is
currently in progress. Of the four entry and exits that the station will
have, we are building one right now and the other three will soon be
completed,” he said.
The TBMs are drilling about 8-10 metres a day. However, this varies depending upon soil condition, the official said.
“Soil
conditions here are very unpredictable and it is quite challenging to
tunnel this stretch. Sometimes it is very rocky and this slows down
tunnelling work. On some days, conditions are favourable and work
progresses fast,” said another official.
Sources said
that it may take another six months for tunnelling work to be completed
at this station. Underground station work is expected to be completed
by April 2015.
Source: http://to.ly/mdO9
