CHENNAI: The work on the first of the twin tunnels from Greenways station to Adyar junction covering 1.2 km was completed after a gruelling 178 days. This will be a major boost for the work being carried out in corridor-3 of Chennai Metro under the second phase.
The work commenced in February 2023 and both tunnels need to pass below the Adyar River for a distance of 300m.
Two earth pressure balancing (EPB) tunnel boring machines - nicknamed Kaveri and Adyar - were engaged for the work. Kaveri has successfully completed the tunnelling drive, while Adyar is currently 277m away from the shaft located at Adyar junction, and expected to reach in November.
The tunnels are at a depth of 15-22m, and the walls have a thickness of 35-40cm. This will connect north-eastern suburbs and core city areas with the IT corridor on Old Mahabalipuram Road, linking Perambur, Chetpet, Nungambakkam, Thousand Lights, Royapettah, Mandaveli, and Madhavaram.
The tunnel has mixed geological conditions, with the bottom being rocky and the top being sandy. There was also hard rock below some portions of the Adyar river, resulting in replacement of 65 cutters. According to sources, tunnelling under a waterbody is challenging because of water pressure.
The boring machines have passed under a few petrol bunks, MGR Janaki college, Andhra Sabha Hospital, Durgabai Deshmukh road and Adyar bridge ramp.
Alandur metro station gets bigger parking facility
To accommodate the increasing passenger demand, Chennai Metro Rail has expanded the parking facilities at Alandur metro station. The newly renovated parking area, located opposite the station behind MGR Statue has been upgraded with paver blocks and can now accommodate an additional 300 two-wheelers. The existing parking facility at the Alandur station can support 1,300 two-wheelers and 180 four-wheelers.