By Lynda Myer
While building a tunnel for a major coastal road project in Mumbai, India, Larsen and Toubro’s tunnel boring machine (TBM) has registered a new world record for monthly lengths.
The intended slurry TBM with 12.19m length is constructing package four of the 10.58km long Mumbai Coastal Road Project, which is a 2km long twin bored tunnel.
In order to form a combined road length of over 4km, this package also involves the construction of a cut and cover section.
Following completion, a 456.72m excavation in one month for the second bored tunnel, this TBM exceed the world record, whereas the previous global record was 455.4m for monthly tunneling by a 13m single shield TBM.
Launching from Girgaon Chowpatty to construct the second tunnel in April, this machine completed the digging process of the first tunnel in January 2022.
Stretching from Priyadarshini Park to Girgaon Chowpatty, the tunnel will pass beneath Malabar Hill, and once completed, it is due to be the largest and deepest bored road tunnel in India.
Providing packages one and five of the project for the Municipal Corporation of Greater Mumbai (MCGM), is up to Larsen and Toubro TBM.
Named Mavala after infantry warriors in Shivaji’s army, the 2,500t TBM is the largest deployed in the country at present.
Due to the delivery of this machine to the site during the height of the pandemic, external experts could not travel so the team took it upon themselves to assemble the TBM with virtual help only. The TBM was then lowered into the launch shaft in a fully assembled form.
In order to commence the second tunnel construction, they rotated the TBM inside the shaft and this act saved them several months to dis-assemble, lift, transport, and reassemble and lower the TBM at a new location.
According to Larsen and Toubro senior executive vice president of civil infrastructure S V Desai: “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 tunneling thanks to our experienced and qualified team. It had given us a huge boost to speed up construction to deliver this iconic and extremely complex project in time and with quality,” added S V Desai.
Including the construction of a 3.82km long section over reclaimed land from Priyadarshini Park to Baroda Palace and interchanges at Amarson Garden and Haji Ali, Larsen and Toubro is also delivering package one of the road project.
