L&T’s Chennai Metro TBM Palar Records Breakthrough at Sterling Road

Larsen & Toubro (L&T) on Wednesday celebrated tunnel boring machine DZ1041’s first breakthrough at Sterling Road Station for the 116.1 km Chennai Metro Phase 2 project.

This milestone marks the third tunnel breakthrough for 45.8 km Chennai Metro Line-3‘s 12 km Package TU-02 connecting Kellys and Taramani Road Junction stations.

Nicknamed TBM Palar, this Ø6.65m earth pressure balance (EPB) machine was manufactured by China Railway Construction Heavy Industry (CRCHI) and had passed factory acceptance tests (FAT) in the summer of 2022.

It was commissioned from Line-3’s Chetpet Station in January 2024 to build the up-line and travelled 708 meters in 260 days to arrive at Sterling Road Station on Wednesday. Along the way, it bored a 52 meter tunnel under Cooum River with an overburden of 6 meters.

Chennai Metro Rail Ltd. (CMRL) had awarded L&T with Package TU-02’s Rs. 2385 crore contract in May 2021 with a 42 month deadline.

Besides constructing twin tunnels between Kellys and Taramani Road Junction, they will build diaphragm walls, entry/exit structures of Chetpet Station, Royapettah Government Hospital Station, Thiruvanmiyu Station, and part diaphragm wall of Greenways Road Station, including launching and retrieval shafts at the above stations.

TBM Palar was L&T’s 4th of 7 machines to get going for building approximately 12 km twin tunnels (total 24 km) between Kellys and Taramani Road Junction stations.

Per CMRL’s press release – “The tunnelling process encountered primarily clay and sand, along with sections of Grade V rock. Notably, the TBMs navigated beneath significant landmarks, including the Chetpet Corporation School, Chetpet Dhoby Ghat, KarukathammanTemple, and various shops along Valluvar Kottam High Road, all without causing any ground settlement. Many residents remained unaware of the TBM operations occurring beneath their structures, underscoring the precision of the work.”

L&T’s TBM Siruvani (DZ1040) had built the parallel down-line tunnel from Chetpet and arrived at Sterling Road in August to mark TU-02’s very first breakthrough.

With this development, a total of 9 tunnels have been completed so far. On the south-side, L&T has recorded three breakthrough for Line-3 on Package TU-02 (Kellys to Taramani Road Junction):

• August 2024: TBM DZ1040 (Siruvani) at Sterling Road – 703m
• September 2024: TBM 1327A (Kaveri) at Adyar Junction – 1228m
• October 2024: TBM DZ1041 (Palar) at Sterling Road – 700m

While on the north-side, Tata Projects has built 6 tunnels for Package TU-01 (Madhavaram – Kellys). 4 of those connect Venugopal Nagar – Madhavaram Milk Colony – Madhavaram High Road stations on the extreme north side, a length of roughly 2.5 km including station boxes.

• June 2023: TBM S98 (Anaimalai) at Venugopal Nagar – 415m
• August 2023: TBM S96 (Nilgiri) at Madhavaram High Road – 1.4 km
• September 2023: TBM S99 (Servarayan) at Venugopal Nagar – 415m
• November 2023: TBM S97 (Podhigai) at Madhavaram High Road – 1.4 km
• June 2024: TBM S98 (Anaimalai) at Otteri Station – 925m
• August 2024: TBM S81B (Kolli) at Otteri Station – 903m

For more updates, check out the Chennai section or my Home Page! Sign up for free instant email notifications on new posts over here. Like this post? Get early-access to updates and support the site over here.

– TMRG