Yesterday TBM Palar, which was launched in January this year, arrived at the Sterling Road shaft after completing its drive on the upline from Chetpet on Corridor 3. Its twin, TBM Siruvani, broke through in August after completing the downline bore. Each tunnel is 708m long.
The tunnelling process encountered primarily clay and sand, along with sections of Grade V rock. The TBMs navigated beneath important landmarks, including the Chetpet Corporation School, Chetpet Dhoby Ghat, Karukathamman Temple, and retail areas.
A particularly challenging segment involved a 52m-long stretch beneath the Coovam River, with only 6m of overburden in clay. Chennai Metro says the operation was executed without incident, maintaining face pressure and alignment without any blowouts.
The Phase 2 project has a total length of 116.1km. The 45.4km Corridor 3 runs north to south across Chennai from Madhavaram Milk colony to Siruseri Sipcot. It will have 28 underground stations and 19 elevated stations.
