Chennai Metro Phase II Tunnelling Begins on Challenging Thiruvanmiyur–Indira Nagar Stretch

Chennai Metro Rail Limited (CMRL) is gearing up to commence tunnelling on one of the most challenging sections of its Phase II project, the Thiruvanmiyur–Indira Nagar stretch, in the coming month. This 650-metre underground stretch, part of Corridor 3 connecting Madhavaram to SIPCOT via Adyar, poses unique engineering challenges due to the presence of high-quality granite.

Two state-of-the-art Tunnel Boring Machines (TBMs) have been deployed to carve twin tunnels along this route. CMRL officials have been preparing the Thiruvanmiyur station site for excavation over the past few weeks. While one TBM has already been lowered into the site, the second is expected to follow shortly.

Excavation at a depth of 22 metres is currently underway, and officials have noted that the presence of hard granite has slowed progress compared to initial estimates. The contractor initially considered controlled blasting to break the rock but opted for chemical disintegration methods to ensure safety and precision. This approach is expected to minimize disruption while maintaining tunnelling efficiency.

Despite the relatively short distance of this underground stretch, CMRL anticipates the TBMs will require nearly a year to complete the twin tunnels. Frequent maintenance, including cutterhead interventions, will be necessary to replace worn-out parts as the machines bore through the granite. These interventions, though time-consuming, are crucial to ensure uninterrupted operations and long-term structural integrity of the tunnels.

Once completed, trains originating from Madhavaram will pass through over 40 locations, including Thiruvanmiyur and Indira Nagar, before reaching SIPCOT. This development is expected to significantly improve commuter connectivity and reduce travel time along the corridor, providing residents with a faster and more reliable metro service.

With Phase II now moving forward on this complex stretch, Chennai Metro is demonstrating its commitment to advanced engineering and urban mobility. The Thiruvanmiyur–Indira Nagar tunnelling project highlights both the technical expertise involved and the city’s continuous push towards modern, sustainable public transportation.