KOLKATA (Metro Rail News): Tunnel borer Urvi is likely to achieve its breakthrough by Thursday of this week, hitting the diaphragm wall below Bowbazar’s Durga Pithuri Lane and crossing the biggest milestone for the project. Engineers of Kolkata Metro Rail Corporation (KMRC), implementing the city’s most ambitious infrastructure project, said tunnel boring machine (TBM S-616) might punch the diaphragm wall below Durga Pituri Lane by Thursday evening of this week
Thus would end the most tedious journey of the Metro corridor project. For it was here at Durga Pituri Lane off Bowbazar that many buildings were razed — after some of them either collapsed or were critically damaged on 31 August 2019 and around 700 residents evacuated as water gushed into a under-construction tunnel. The giant machine digging the westward tunnel ran into an aquifer resulting in water seepage and large scale subsidence.
Tunnelling was stopped as Chundi, the TBM digging the westbound tunnel, became defunct. In February 2020, Urvi, the twin TBM digging the east-bound tunnel, restarted and continued till its destination Sealdah station. On 4th January 2021, a recommissioned Urvi started its journey to bridge the last 800M gap of the westward tunnel started. Urvi’s breakthrough will finally mark the completion of the TBM-driven tunnels of the RS. 8,575.98 crores of East-West Metro project.
A diaphragm wall is built to integrate the tunnel with the station. In this case, the diaphragm will bridge the two portions. Had it not been for the second wave of the pandemic, KMRC and contractors ITD ITD-Cementation would have celebrated the breakthrough with much fanfare. At end of April, many ITD’s staff members got infected. The front office had to be kept shut from 2nd May 2021 due to the break of the contagion chain.