Tunnelling work for Metro phase II at Madhavaram to begin by mid-October

The first tunnel boring machine that arrived from China has been lowered into the site last week, say CMRL officials. A month later, a second TBM will also be put into use

Madhavaram will witness the first tunnelling operations for Metro Rail’s phase II project, which will begin by the middle of October.

The first tunnel boring machine (TBM) that arrived from China more than two months ago was lowered into the construction site last week, according to the officials of Chennai Metro Rail Limited (CMRL). At Madhavaram, one TBM will start the tunnelling process initially and drill towards Kellys to build an underground stretch. A month later, a second TBM will also be put into use.

In the three corridors — Madhavaram to SIPCOT, Light House to Poonamallee and Madhavaram to Shollinganallur — of the 118.9-km phase II project, work will first commence on the underground stretches from Madhavaram to Kellys (a part of Madhavaram-SIPCOT corridor).

“Usually, we give a gap of a few weeks between the deployment of the two TBMs. It is always better to operate with a space of 100 m or more. Before starting the tunnelling work at Madhavaram, we completed surveys and utility diversion work. We have to track and plug the borewells within residences,” an official said.

Later, before the end of this year, two more TBMs will start working between Kellys and Taramani. Gradually, the underground work will expand to the other areas of the city too.

Chennai Metro Rail will use 23 TBMs to build the underground stretches in different locations in the phase II project, built at a cost of ₹61,843 crore. Most of the machines deployed this time will be remanufactured in the country, including 12 machines from Tamil Nadu and one from Pune. There will also be one that will come from Germany and five from China, another official said. These will help quicken the construction of the underground stretches.

“Some of the machines have already arrived and will soon gear up for the work. TBMs can usually bore nearly 8-10 m a day, but if the geological conditions are tough, it could slow down to as much as 5 m. We have been planning well to see to that there aren’t too many delays in the completion,” he added.