Breakthrough of CMRL’s tunnel boring machine at Kellys delayed by a few months

Travel quickly from Purasawalkam to Kellys with Chennai Metro Rail's Phase II Project tunneling progress.

At present, travelling to areas such as Purasawalkam and Kellys from the southern parts of the city could be time consuming owing to traffic congestion. But a few years down the line, you can hop into a Metro Rail train and reach these places quickly.

As a first step, the tunnel boring machine (TBM) of Chennai Metro Rail Limited (CMRL), which began drilling in Purasawalkam for the Phase II Project has reached Kellys. But it has to wait for the breakthrough for another couple of months as the construction of the shaft is still under way.

According to CMRL officials, they have started constructing portions of the underground network for corridor 3, which connects Madhavaram to SIPCOT via areas such as Purasawalkam, Nungambakkam, Adyar, and Old Mahabalipuram Road. Many sections of this corridor are underground, while a few are elevated.

To link Purasawalkam to Kellys, the TBM was lowered in Purasawalkam in December last year, drilling a distance of nearly 300 m to reach its destination. “Since one of the station tenders was cancelled a few years ago, the construction of the shaft and station in Kellys has been delayed. The TBM is waiting outside the site of the station. When the shaft is completed, the TBM can enter the station. We expect this to happen in August. Subsequently, the TBM will be taken out of this site and used in another location,” an official said.

Since Purasawalkam is a congested area, CMRL could deploy only one TBM at a time. The second one will be launched after a few months.

There were no particular challenges in tunnelling between Purasawalkam and Kellys, and it was a smooth drive, officials said.

“The machine encountered sandy and clayey soil conditions during the process. Since this was a short distance and the machine did not tunnel under very old buildings, we could complete the work without too many settlement issues,” another official said.