CMRL undertakes testing for first TBM in Corridor 4

CHENNAI: The Chennai Metro Rail Limited (CMRL) conducted the factory acceptance test for the first tunnel boring machine (TBM) in Corridor 4 (from Lighthouse to Poonamallee bypass) in underground portion 1 of the construction.

CMRL is currently constructing the underground Metro rail project in Corridor 4 in two portions (UG 1 and UG 2), each of which contains four kilometers of twin tunnels.

For the completion of nearly 16 km of tunneling, four tunnel boring machines have been planned by CMRL, considering both the upline and downline tunnels.

As per CMRL press note, the TBMs was manufactured by German company M/s Herrenknecht, which will be utilised by contractor M/s ITD Cementation India Limited in corridor 4. Owing to this, at the HK factory in Ponneri, the first factory acceptance test of the first tunnel boring machine was held in the presence of CMRL projects director T Archunan.

The TBM named S1073B is 6.670M bore diameter and 110-meter-long earth pressure balance machine. TBM weighing 700MT will be dismantled to be transported and placed at the destination at Light House Station, Marina beach.

Subsequently, to receive the TBM, the construction of a launching shaft is currently underway in Light House Station, which is expected to be ready by May.

The TBM will be launched downline of Corridor 4 and will mine at a maximum depth of 29 meter below ground starting from Light House, Kutchery Road, Thirumaylai, Alwarpet, Bharatidasan and lastly scheduled to arrive at Boat Club in May 2025, added the press note.

CMRL's Phase II Metro rail construction is currently undertaken for 118.9 km with 128 stations in three corridors.