Chennai Metro’s TBM S81B Achieves Breakthrough at Otteri Station

Chennai ( Metro Rail News): Another day, another achievement. TBM S81 B with the nickname Kolli, commissioned by Tata Projects Ltd. recorded a breakthrough at Otteri station of Line 3 in 116.1km Chennai Metro Phase 2.

In July 2023, Tata Projects deployed TBM (Kolli ) on the south shaft of Ayanavaram Station of the 45.8km Line 3 ( Mandharam station – Siruseri SIPCOT ). After covering a distance of about 903 m TBM Kolli reached Otteri station in just 13 months.

TBM S18 B ( Kolli) 

Kolli is a Terratec Earth Pressure Balance (EPB) machine with 06.61 km. During the excavation, the machine encountered more than 100 bore wells and to avoid any inconvenience it took two sharp curves of radius 220 m and 280 m respectively.

After its first breakthrough in the Pune metro, In December 2022, TBM S18 passed the FAT   (Factory Acceptance Test ) before being deployed in the Chennai Metro Phase 2.

Scope Of Work  

This assignment of Tbm Kolli falls under Package TU-01.  In May 2021, Chennai Metro Rail Ltd. (CMRL) awarded Tata Projects with Package TU-01  with a 42-month deadline. The total cost of the project is Rs 1999 crore. Package TU-01 is a 9 km long section on Line 3 of Chennai metro Phase 2.

The work scope of TBM Kolli and 6 other TBMs under Package TU-01 includes the construction of a 9 km twin tunnel (totalling 18 km) from the TBM retrieval shaft near Venugopal (line 5) to Kelly station (Line 3) and the construction of diaphragm walls and entry and exit structures of Madhavaram Milk Colony Station, Murari Hospital Station, Ayanavaram Station and Purasaiwakkam High Road Station. 

As of now, Tata Projects Ltd. has recorded 6 tunnel breakthroughs under the Package -TU-01.