Breakthrough of a tunnel boring machine (TBM) working on one of the longest and deepest water tunnels ever built in Asia marks a milestone on a scheme that has also set new record rates for tunnelling in India.
The Robbins Main Beam TBM has been used to construct the 8.3km long Mumbai Water Tunnel at depths of up 10 109m below ground level and delivered production rates of 870m a month and up to 58m per day.
“Both the daily and monthly progress we have seen are records for TBM tunnelling in India,” said project owner Unity’s Pravin Titare. These rates have been achieved despite the route encountering difficult ground including basalt rock, fractured ground and water inflows on the 21 month long tunnelling work.
The water tunnel is a key part of the city’s plans to ensure consistent supplies of clean water to its 20.5M residents. Existing fresh water systems are frequently contaminated during the monsoon season.