The tunnel boring machine ‘Urvi’ deployed on East-West Metro’s Underground Section has crossed over to the other side of BB Ganguly Street, digging past the Bank of India building and heading for Sealdah.
On the last leg of tunnelling, Urvi, digging the east-bound tunnel, will cover another 450m to reach its destination, Sealdah station. To ensure no harm comes to it, the Bank of India building on the BB Ganguly Street-Amherst Street intersection has been propped up from all sides for strengthening even though the TBM’s burrowing has been extremely slow.
Urvi was expected to have made 1,790 rings till Wednesday this week. Commissioned in January last year to build the last leg of East-West Metro, covering 2.45km between Esplanade and Sealdah, the machine has drilled around 2km from Esplanade so far.
It operates in a circular fashion to bore through the soil by creating rings out of pre-cast concrete segments. But the journey has been saddled with challenges and fiascos what with a largescale land subsidence after another TBM hit an aquifer on August 31 last year and the work being suspended for several months. It finally resumed but again, had to be stopped for the pandemic. Subsequently, the boring resumed but engineers and workers contracted the novel coronavirus, leading to another break.
After tunnelling was resumed earlier this month, officials of Kolkata Metro Rail Corporation, agency implementing the 16km Metro corridor between Howrah Maidan and Salt Lake’s Sector V, and contractors ITD ITD-Cementation hoped to complete the remaining distance by mid-September. After languishing below Bowbazar Girls’ School for a while, TBM Urvi took some time to cover the few yards till the Bank of India crossing because of a technical snag that made it take short breaks.