Vaigai finishes boring in dense city stretch

CHENNAI: A tunnelling milestone was achieved on Friday as CMRL completed a breakthrough at Mandaveli station on Corridor 3 of the Phase II expansion. The upline tunnel boring machine (TBM) Vaigai broke through after a 610-day drive from Greenways station, completing a 775-metre stretch beneath one of the citys most densely built-up areas. The works form part of the 45.8-km Corridor 3, which will link Madhavaram to SIPCOT. T Archunan, director (projects), CMRL, along with officials from the agency, consultants and Larsen & Toubro, which is executing the tunnelling contract, were at the spot. The Vaigai TBM passed beneath 75 buildings with an overburden ranging from 9 to 12 metres, navigating multiple sewer, water and power utilities in the Mandaveli shaft area. This was one of the most technically challenging stretches on the corridor. Utility diversions and ground conditions required careful planning and multiple cutterhead interventions, a release said. This is the third TBM breakthrough achieved by CMRL this month.