MMRC completes 100% tunnelling of Colaba-Bandra-SEEPZ line

The final breakthrough in the tunneling process was made by Tunnel Boring Machine (TBM) Tansa 1 the Mumbai Central Metro Station. In civil engineering parlance, a breakthrough is defined when a TBM, lowered in a particular shaft, manages to bore through the defined geological route and emerges successfully at a designated end.

The breakthrough, the 42nd one made by a TBM, was made after a challenging drive of 837 m from Mahalaxmi Metro Station to Mumbai Central Metro Station up line in 243 days, using 558 concrete rings.

“It was with great pleasure that I witnessed the final breakthrough today. It marks 100 per cent tunnelling of Metro 3 corridor. Tunnelling below Mumbai’s heritage precincts, in close proximity of old dilapidated buildings, existing Metro line, railway lines and water body with different and sometimes difficult geological conditions has been a daunting task,” said Ashwini Bhide, MD of MMRCL.

“We used advanced technology without compromising on the safety of workers. This was a daunting task for the MMRCL team, along with general consultants, contractors and joint ventures. Once operational, Metro 3 aims to provide a speedy, comfortable and safe commuting experience to the Mumbaikars,” said S K Gupta, Director (Projects), MMRCL.

With the breakthrough, the tunneling work of the entire line is complete. The overall progress of the project stands at 76.6 per cent.

The tunneling for Metro 3, comprising 33.5-km long underground stretch, was mainly done by 17 TBMs.

The tunneling work began five years ago with the arrival of the first TBM on September 5, 2017, which was lowered at Naya Nagar shaft on September 21.

With tunneling work complete, phase 1 of the line, which will stretch from Aarey to Bandra Kurla Complex (BKC), is expected to be opened for public by 2023. The second phase from BKC to Cuffe Parade is expected to be operational by 2024.

Besides the tunnelling work, segment casting work was also carried out simultaneously. About 2,86,000 (2.86 lakh) cubic metric tonnes of concrete and 29,500 metric tonnes of steel were used to construct segment rings.