By rosebell
Following that TBM Mullai, which has been started up by Tata Projects Ltd on May 5 2025, has arrived at Kolathur Station North shaft after completing a 246m-long drive from Kolathur Ramp,Chennai Metro Rail Ltd (CMRL) has recorded a simultaneous breakthrough and TBM launch on Corridor 5 of its Phase 2 expansion.
A low overburden of 1.8m, a steep gradient of -3.8%, as well as the need for ground protection in a region with heavy traffic, are the main challenges faced during the drive.
With the aim of constructing the tunnel, also TBM Kurinji has been commissioned from the Kolathur South shaft to Srinivasa Nagar station. The 1060m bore includes Grade 4 and 5 rocky strata and a 230m curve.
“This is a unique achievement and a first in our country as a TBM has been launched and another TBM breakthrough has also been done simultaneously in the same underground metro station,” CMRL said.
While Chennai’s Phase 2 has multiple corridors, the 47km-long Corridor 5 comprises 5.8km underground and 41.2km of elevated track and four TBMs, Kurinji, Mullai, Marutham and Neithal, are being deployed in this section.
