The construction of a base slab, key to bridging a gap at the East-West Metro site in Bowbazar, was completed on Friday morning, said project officials.
Forty-five people living in three buildings that were said to be under the “influence zone” of the work were evacuated as a “precautionary measure” at the start of last week (February 26-27).
“The work was over in the early hours of Friday and by Friday night, the residents who had been accommodated in a couple of hotels in Bowbazar were back at their homes,” said an official of the Kolkata Metro Rail Corporation,” the implementing agency of the 16.5km East-West Metro project.
The gap was in the form of a retrieval shaft from where the two tunnel boring machines had been pulled out.
The covering of the shaft would be a “significant” moment for the much-delayed project.
“Once the shaft is shut, we can bring a rake from Sector V to Esplanade. We can have trial runs between Esplanade and Howrah Maidan,” said an official of KMRC.
The construction of a concrete structure to close the shaft led to a water leak on May 11, 2022 — the second of three accidents since 2019 — triggering cracks in houses in the area and displacement of many people.
The work to plug the shaft was stalled since the accident in May because of a fear of a possible rerun.
The work started in the third week of February this year after a series of tests, which, officials said, indicated that the soil was safe.
Construction of half of the balance 9m was finished within six days.
The construction of the remaining 4.5m started on February 27, after the local residents were evacuated.
“Now, that the base slab is complete, the side walls will be cast. Construction of the roof will be the final stage,” said the KMRC official.
“There was a gap in the west-bound (Howrah-bound) tunnel. The gap will be joined when the shaft is shut,” said an official of ITD-ITD Cementation, the contractor building the twin tunnels on the Esplanade-Sealdah stretch.
“This base slab had to be finished. There are some support systems inside the tunnel. Once they are removed, a train can be taken till Esplanade for trials between Esplanade and Howrah Maidan,” he said.
The construction of a ventilation shaft at Raja Subodh Mullick Square and four cross passages for emergency evacuation are two major challenges that remain in the 2.5-stretch between Esplanade and Sealdah, he added.
