Kolkata East-West metro corridor underground tunnelling work is to take 10 more months to be finished, an international expert committee appointed by the KMRC announced on Friday.
Also, the safety of the people residing in dilapidated buildings – many of that was built over 120 yrs ago, in one part of the route is a cause for concern, Leonard John Endicott said a geotechnical expert and committee head. “The biggest challenge is that many buildings in the area are in poor condition. Our concern is the safety of the people,” he added further.
“The corridor tunnelling work was postponed after one of the two tunnel boring machines hit an aquifer on August 31, 2019, in Bowbazar area leading to severe ground subsidence and the collapse of buildings, will resume in full swing in a day or two,” said Endicott.
With the TBM getting destroyed beyond repair in the accident, the work will have to be finished with one tunnel boring machines only. The existing TBM has been moved a few rigs to check for all safety parameters put in place to assure that there is no repeat of the earlier incident. “We are supercautious,” Endicott said.
Earlier to that accident at Bowbazar, two TBMs were working parallelly, boring tunnels for the up and down lines of the East-West Metro corridor. “It will take around five months for the TBM to go up to Sealdah from Bowbazar. Then, it will take three months for the TBM, which is a huge machine, to turn around.
“It will take another two months for the machine to dig on another side and reach up to the point where the first TBM had cut the tunnel,” the geotechnical expert stated. He told that the working TBM had been upgraded and it now has 50% more capacity to assure that the ground holds throughout tunnelling work.
“Special measures have been taken to ensure that water does not seep into the tunnel,” he said that the adding that work will be stopped within 60 minutes of noticing any abnormality throughout tunnelling in the area.