CHENNAI (Metro Rail News): On 31 march 2023, the factory acceptance test (FAT) of the tunnel boring machine (TBM S1074B) manufactured by a German company, M/s Herrenknecht, was successfully conducted for the underground construction of line 4 of CMRL’s phase 2 project in the presence of the General Manager of CMRL (Construction) Mr. R Ranganathan and various officers from General Consultants, M/s AEON Consortium at HK factory in, Ponneri Thaluk, Alinjivakkam village in Thiruvallur District of Chennai.
The phase 2 project is 118.9 kilometers and an ambitious phase with 128 stations divided into three corridors: Corridor-3 starts From Madhavaram to Siruseri -SIPCOT is 45.8 km, whereas Corridor-4 is From Light House to Poonamalee Bypass of 26.1 Km and the Corridor-5 begins From Madhavaram to Sholinganallur of 47 Km. The underground section will split into twin tunnels (UG 01 and UG02) at every 4 Km in both upline and downline tunnels.
For completing 16 Km of tunneling, 4 TBM have been implanted, and the name of the machine is Krishna-2 which is a 6.670 M bore diameter and 110 m long EPB (Earth Pressure Balance) Machine with a weight of 700 MT. The machine will be dismantled in parts and carried to Panagal Park Station, T Nagar.
The TBM will be launched from Panagal Park through Nandanam, which will mine at a maximum depth of 29 m in the Downline of corridor-4 below ground level and by September 2024, it will finally reach Boat Club connecting Kodambakkam Flyover.