Namma Metro: Why Tunnel Boring Machine ‘Lavi’ got stuck 200 times

Rocky conditions, oxygen shortage (due to Covid) and lack of manpower were some of the issues which caused the delays to the project that started on Feb 10 in 2021.

Sometimes a journey is more defining than the destination and it can get really boring – literally. Don’t worry, we are talking about the Bangalore Metro Rail Corporation Limited’s Tunnel Boring Machine (TMB) Lavi had to go through before it could retire. The machine was interrupted 200 times before it could complete a 14-month trip on MG Road, which set back its deadline by two months.

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Rocky conditions, oxygen shortage (due to Covid) and lack of manpower were some of the issues which caused the delays to the project that started on Feb 10 in 2021.

A senior Metro official told The New Indian Express: “The biggest issue faced when carrying out work using any TBM is the damage to the discs on the cutter head. In case of Lavi, the discs were damaged more than that encountered with any TBM before.”

He said four every six metres drilled, four discs would get damaged, a problem which was exacerbated when passing through a dolerite zone. Dolerite is soft outside and much harder inside.

This occurrence repeated itself 200 times when drilling the 1000-metre stretch.