Mumbai Coastal Road Project: L&T Creates World Record In Tunnel Boring

Larsen and Toubro (L&T) has created a world record in the tunnel boring category as its Tunnel Boring Machine (TBM) ‘Mavala’ engaged in the prestigious Mumbai Coastal Road Project excavated 456.72 metres length in a month.

TBM ‘Mavala’, named after Shivaji’s army’s infantry warriors, is the country’s largest deployed, with a diameter of 12.19 metres.

Weighing approximately 2,500 tonnes, the TBM ‘Mavala’ broke the previous global record of 455.4 metres for monthly tunnelling done by a 13-metre single shield EPB (Earth Pressure Balance) TBM.

“This is a huge achievement for the entire construction industry worldwide and truly an engineering feat to be proud of. We achieved this speed of tunnelling thanks to our experienced and qualified team. It has given us a huge boost to speed up construction to deliver this iconic and extremely complex project in time and with quality,” S V Desai, Whole Time Director and Senior Executive Vice President (Civil Infrastructure), L&T, said.

“I take this opportunity to thank our customer, the Municipal Corporation of Greater Mumbai (MCGM), for reposing faith in us and supporting us through this whole process, as well as our employees without whom this could not have been achieved.” he added.

The Mumbai coastal road project involves the construction of 12-metre-wide twin tunnels under Malabar Hill (75 metres deep) and Girgaum Chowpatty (25 metres deep) between Priyadarshini Park and Marine Drive in South Mumbai. The length of each is 2.07 km from Priyadarshi Park to Chhoti Chowpatty at Marine Drive, close to the landmark Chowpatty beach at Girgaum.

In Dec 2020, Larsen & Toubro commenced the deployment of TBM Mavala – the largest tunnel boring machine (TBM) ever to be used in India – at the Priyadarshini Park launch ramp for building twin tunnels of the coastal road project.

TBM Mavala was manufactured by China Railway Construction Heavy Industry Co. Ltd. (CRCHI).

TBM Mavala completed the first tunnelling work on January 11, 2022. It began the excavation work for the second tunnel on March 30. Mavala excavated around 600 metres of the second tunnel within three months.

Mumbai Coastal Road Project

Once completed, the ambitious 10.58-km-long coastal road project (phase 1) will add an 8.5 km long and 20-metre wide sea promenade to the city between Priyadarshini Park at Napean Sea Road and the Worli side of the Bandra Worli Sea Link. The first phase of the coastal road is being built by the Brihanmumbai Municipal Corporation (BMC) at an estimated cost of Rs 12,500 crores to speed up the suburban commute to and from South Mumbai.

The project is to be constructed in two phases. The second phase involves connecting Bandra Sea Link to Kandivali Junction. Work on this stretch is yet to commence.

While Larsen and Toubro is executing Package 1 and 4 of the coastal road at Rs 7,489 crore, a joint venture between Hindustan Construction Company (HCC) and Hyundai Development Company (45 per cent) is executing Package 2 and 3 at the cost of Rs 2,126 crore.

The coastal project is set to dramatically transform the coastline in South Mumbai, which has a long history of reclamation. Once complete, the road will extend the coast up to 100 metres inside the sea.