Metro Rail study digs more deeper

Metro Rail study digs more deeper

VIJAY TIMES NEWS

Bangalore: While a study conducted five years back was not in favour of Bangalore having an underground rail system as the subsurface was not conducive to it, a subsequent Delhi Metro Rail Corporation (DMRC) study took an opposite view saying the city's geology could indeed withstand such a system.

Bangalore Mass Rapid Transit Limited (BMRTL) had commissioned the 2000 study, which was conducted by L&T Ramboll, to assess geotechnical features of the city and submit a report at a time when the elevated light rail transit system (ELRTS) was a candidate mode of mass transport.

L&T Ramboll said in case of an underground railway system (as in Metro Rail) excavations through weathered rock would be difficult. The study observed weathered rock was seen at relatively shallow depths, thickness of the layers varying from 0.5 metres to 18 metres. Moreover, soft rock was not encountered in any of the bore holes during the study.

"Minor blasts would have to be resorted to ...(which) would result in vibrations affecting structures nearby," it said. The depths of each underground station, as planned for the Metro Rail project, varies between 18 metres to 25 metres.
However, the study states even at 10 metres the rocks would be weathered making excavations difficult.

BMRTL officials said an extensive study conducted by DMRC in 2003 had concluded that Bangalore's geology was conducive to withstand in the metro. They said that unlike New Delhi, where soil in some parts was shallow, that in Bangalore could withstand underground excavations and tunneling as required for the Metro Rail.