Three tunnelling breakthroughs have been recorded on Chennai Metro Phase II in three days.
On September 29, TBM Kaveri at Kilpauk Medical College Station on Corridor 3’s down line. This was followed on September 30 by TBM Maruthan arriving at Villivakkam Station on Corridor 5’s down line, and TBM Adyar breaking through at RK Salai Station on Corridor 3’s down line on October 1.
Larsen & Toubro is delivering the 12km underground section of Corridor 3 between Kellys and Taramani, while Tata Projects is responsible for Corridor 5, which has a total tunnel length of 7.88km.
On Corridor 3, TBMs Kaveri and Tamarabharani began tunnelling between Chetpet Station and KMC Station in February 2024. TBM Tamarabharani completed the upline drive in November last year.
Tunnelling this 685m stretch, the TBMs had to negotiate several critical structures, including five live Southern Railway Tracks near Chetpet Station with an approximate overburden of 18m; the Chetpet Eco Park lake and several buildings of Kilpauk Medical college with an overburden ranging from 21-26m; and existing Chennai Metro Phase I tunnels with a minimum clearance of 6.1m.
TBMs Bhavani and Adyar were launched on the drive between Royapettah Station and RK Salai Station in September 2024. The upline TBM Bhavani completed its 910m drive in October last year. TBM Adyar’s breakthrough – the 10th on the TU02 Contract – was made after completing a 915m drive through silty sand and with an overburden of 9-13m.
Tata Projects launched TBM Maruthan on April 24 this year to bore the 601m tunnel between Villivakkam Railway Station and Villivakkam Bus Terminus Metro Station. The alignment’s challenges included tunnelling beneath five operational lines at Villivakkam Railway Station and the requirement for ground protection in a heavily residential area.
Chennai Metro Phase II has three corridors and will expand the city’s metro by 118.9km and 128 stations. It is due to be completed by the end of 2028.
