Ten years after the first tunnel boring machine (TBM) was pressed into service at Nehru Park, Chief Minister M.K. Stalin inaugurated tunnelling operations for the ₹61,843-crore Phase II Project at Madhavaram on Thursday.

The made-in-China TBM started drilling the earth from Madhavaram Milk Colony station at a depth of nearly 20 metres. One more machine will be pressed into service from this site and head in the same direction towards Kellys. These two machines are expected to bore the earth at a speed of 10 metres under the present geological conditions and the next stop will be Madhavaram High Road.

Chief Minister M.K. Stalin launching the drilling by tunnel boring machine (TBM) for Chennai Metro Rail Phase II project at Madhavaram in Chennai on Thursday. | Photo Credit: B. JOTHI RAMALINGAM

Among the three corridors of the Phase II project — Madhavaram to SIPCOT (Corridor 3 - 45.8 km), Light House to Poonamallee (Corridor 4 - 26.1 km) and Madhavaram to Shollinganallur (Corridor 5 - 47 km) — this work has started under the Madhavaram to SIPCOT corridor. In corridor 3, from Madhavaram up to Taramani, Chennai Metro Rail Ltd. (CMRL) will build underground stations and tunnels and after that, the track will climb up as an elevated section all the way up to SIPCOT. Seven TBMs will used to drill underground tunnels between Madhavaram and Kellys and eight from Kellys to Taramani. These two TBMs at Madhavaram weigh nearly 600 tonnes and measure 100m in length.

It will take nearly 140 days for this machine to drill the earth from Madhavaram Milk Colony to Madhavaram High Road, a distance of 1.4 km. “At Madhavaram High Road, the TBM will be taken out, dismantled and relaunched again before proceeding to the next station. This process will take about 45 days. While one TBM has started functioning, the next one has been lowered into the site as well and will be operated within a few weeks,” an official of the CMRL said.

Officials said the stretch between Madhavaram to Kellys largely has marine soil and it will be relatively easier to complete the tunnelling work when compared to the stretch between Adyar and Taramani where it is mostly hard rock and therefore, a challenge to create the tunnel.

#Chennai Metro Rail's phase II tunnelling work begins at #Madhavaram. Two tunnel boring machines will bore the earth from Madhavaram to Kellys. This machine that weighs nearly 600 tonnes and has a length of 100 metres is expected drill nearly 10 metres a day @THChennaipic.twitter.com/8YVa8xdkdB

Meanwhile, CMRL officials said the Phase II is temporarily being implemented as a State project till the Union government approves it.

While the construction work has picked up pace, so far, CMRL has finalised 15 contracts for civil work and two contracts for the system work.

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Printable version | Oct 14, 2022 12:35:40 pm | https://www.thehindu.com/news/cities/chennai/chennai-metros-phase-ii-tunnelling-work-gets-under-way-at-madhavaram/article66005369.ece