Tunnel Boring for Greenways Road Metro Extension Begins in September
Posted on: 08/Aug/2023 11:46:32 AM
Work on the Greenways Road metro extension is set to commence in September, with the tunnel boring machine (TBM) named Kaveri starting its underground journey near the Adyar junction. The TBM will tunnel 20 meters beneath the river to create a 400-meter-long passage. Currently positioned 120 meters away from the river, the machine`s progress is deliberate at 1.5 meters per day due to the presence of structures like a petrol station and a college on the road surface. The tunnel will span 1.2 km between Greenways Road metro station and Adyar junction.
Engineers anticipate a potential slowdown to 1 meter per day as the TBM enters the riverbed, a challenging phase due to water pressure. The tunnel wall`s thickness, initially 35cm, may be increased to 40cm or 45cm to accommodate higher pressures. Waterproofing methods will seal segment gaps to prevent water seepage.
The completed tunnel will feature a crown 7 meters below the riverbed. This extension is part of the 45.4km Corridor-3 from Madhavaram Milk Colony to Siruseri Sipcot. Phase 2 of the project, covering 116.1km, is projected for public use between 2025 and 2028. Additionally, tunnels will be constructed beneath Chetpet lake as part of this phase. A tunnel boring machine is expected to be deployed at the Chetpet site in September after preparations at the launching shaft.
