With safety checks and trial runs having been completed, tunnelling work at the Nehru Park site of Chennai Metro Rail Limited (CMRL) is all set to begin.
Two tunnel boring machines (TBMs) imported from China have been assembled.
Explaining how the TBMs work, a CMRL official said: “Details of the necessary pressure to be applied and depth until which the tunnel would have to go have been pre-determined and fed into the system. Simultaneously, experts will monitor the working of the machines.”
The system being used is an automated numeric-controlled mechanism with the ground information report, and details of the geotechnical investigations have also been incorporated. The TBMs, with a diameter of 5.8 m, will be positioned 9 m below road level.
With the launch of the TBMs, work on Chennai Metro advances to the next major step. Tunnelling, among the most significant operations in the construction of underground stations, will begin at Nehru Park, near Pachaiyappa’s College, and proceed towards Egmore. The second machine will be launched exactly after a month following the launch of the first. This stretch is part of the underground network, from Egmore to Tirumangalam. A total of 11 TBMs are to be used for the construction of the city’s underground metro network.
Corridor II covers Chennai Central – along EVR Periyar Salai – Vepery – Kilpauk Medical College – Aminjikarai – Shenoy Nagar – Annanagar East – Anna Nagar 2nd avenue – Tirumangalam – Koyambedu – CMBT – along Inner Ring Road – Vadapalani – Ashok Nagar – SIDCO – Alandur – up to St. Thomas Mount. The stretch from Koyambedu to St. Thomas Mount is an elevated stretch.
L&T contractors engaged for construction of the underground station at Nehru Park, have roped in Chinese experts to handle the TBMs. They are here for the Chennai Metro project as part of an agreement among CMRL and L&T and the China-based Shanghai Urban Construction Group (SUCG).
