Special tunnel boring machines will be used for the stretch between Royapettah and Taramani.
What’s it about? The next few years will see the Metro Phase 2 construction at full speed. The CMRL plans to use two specialised tunnel boring machines for some underground portions. It’s because there could be some geological challenges.
- Beyond Kelly’s till Royapettah, the soil conditions gradually change with sand, marine clay, and some rocky strata. After Royapettah, there’ll be more rock. At Taramani, it’ll be mostly hard rock.
- Usually, the machines can bore 10 metres a day. However, with hard rock, even special machines can drill only 3-4 metres a day. Between Kelly’s and Taramani, 8 machines will be used.
Progress and project details: As part of the 45.9-km stretch of Corridor 3 from Madhavaram to SIPCOT, the tunnelling work has already begun. In phase 2, the stations will be built at a depth of 18-20 metres. In some locations like Mylapore and Taramani, it’ll be 25 metres.