Coastal road project: Civic body to use Austrian technology to build tunnels

The project will see 3.45-km long twin tunnels running from the Princess Street flyover to Priyadarshini Park, under Girgaum Chowpatty and Malabar Hill.

The NATM, which is said to have strong adaptability for different geological and groundwater conditions, will be specially used in areas where the tunnel boring machine (TBM) will be difficult to manoeuvre and also to widen the tunnels. “The NATM will be used to avoid the typical cut and cover method, like in TBM. It is a costly method, however, it will reduce the time taken in tunneling work,” said Additional Municipal Commissioner Sanjay Sethi.

While the civic body has begun a geo-technical survey at Amarson Garden in Worli and constructed a temporary bund (retention) wall for the project, the tunneling work will only commence after the monsoon next year, Sethi added.

The BMC is set to reclaim more than two acres near Girgaum Chowpatty and Priyadarshini Park for the launching shafts of its 12.2-m wide TBM, which will excavate the underground twin tunnels.

The coastal road, which will run along the city’s western seafront, is envisioned to provide swift travel from the western suburbs to south Mumbai. Last month, the BMC gave its final approval to the construction of the first phase of the road — a 9.98-km road between Princess Street flyover and Bandra-Worli Sea Link (BWSL). The construction work, which is divided into three parts, will begin simultaneously. The work is expected to be completed in the next four years.

Along with the BMC, the Mumbai Metro Rail Corporation will also adopt the new technology for parts of its tunneling work for Metro 3 project, which is completely underground, running between Colaba-Bandra-Seepz. The work is set to begin in January.