Chennai: CMRL bores 246-metre tunnel, reaches Kolathur station

CHENNAI: In corridor 5 of Chennai Metro Rail phase II construction, the tunnel boring machine (TBM) Kurinji has completed tunnelling work to the length of 246 metre, reaching Kolathur station.

The Chennai Metro Rail Limited (CMRL) as part of phase II Metro Rail construction in the city is constructing three corridors for 118.9 km. Part of it is corridor 5 from Madhavaram to Sholinganallur for a distance of 47 km.

The corridor five consists of 5.8 km underground and 41.2 km elevated stations with four TBMs – Kurinji, Mullai, Neithal, and Marutham. The underground section of corridor 5 includes 5 stations and 2 ramps with a total length of 5.8 km, executed by Tata Projects with funding support from JICA.

TBM Kurinji achieved its first breakthrough at Kolathur station north shaft on Thursday. Tunnelling began in February. Currently, Kurinji has reached Kolathur ramp towards Kolathur station covering a length of 246 metres.

As per a CMRL press note, “The main challenges faced during this drive included extremely low overburden of 1.8 metres, a steep gradient of 3.8% and the requirement for ground protection in the middle of Inner Ring Road (IRR), which is subject to heavy traffic.”