Australian-based TBM manufacturer, TERRATEC, celebrated the delivery of the first two of a number of new Tunnel Boring Machines (TBMs) destined for the Mumbai Metro’s 33.5-km Line 3 project, in India, following successful factory acceptance tests earlier in August.
The first of these was a 6.68-m diameter dual-mode hard rock TBM (T58) that will be one of two new machines deployed by the Hindustan Construction Company – Moscow Metrostroy JV to build the twin tunnels on the line’s 4.049-km UGC-02 contract (Chhatrapati Shivaji Terminal Station – Mumbai Central Station), which was awarded by the Mumbai Metro Rail Corporation Ltd (MMRCL) in July 2016.
The T58 machine, along with its sister machine (T59), will be deployed later this year from the Chhatrapati Shivaji Terminal TBM launch shaft towards Kalbadevi Station and onward to the Mumbai Central Station TBM receiving shaft for a total of four tunneling drives over the course of the project.
The second machine delivered in August (T60) was the first of three new TERRATEC 6.68-m diameter dual-mode hard rock TBMs ordered by the J. Kumar – China Railway No. 3 Engineering Group JV for the excavation of sections on the line’s 4.94-km contract UGC-05 (Dharavi Station – CSIA T1 TBM receiving shaft) and 4.45-km contract UGC-06 (CSIA T1 Station – Marol Naka TBM receiving shaft), which were also awarded last July.
These versatile TERRATEC single shield TBMs are equipped to operate in either open or closed mode in the predominantly fresh and slightly to moderately weathered Basalt and Breccia that are anticipated on these contracts. The robust hard rock cutterheads are mounted with heavy duty 17-in. disc cutters, which are interchangeable with ripper tools, and feature large bucket openings that provide a 10% opening ratio.
Other state-of-the-art features include 2,000-kW electric variable frequency drives that allow the cutterheads to cut efficiently in harder rock zones at maximum speeds of 7 rpm and deliver an exceptional torque of 8,000 kNm to cope with more fractured zones of ground along the alignment – as well as active shield articulation and built-in two-component backfilling grout systems.
In addition to the new TBMs, in July TERRATEC also completed the successful factory acceptance testing of two re-manufactured 6.61-m diameter mixed/rock Earth Pressure Balance machines (S63 and S64), which will also be deployed by the J. Kumar – China Railway No. 3 Engineering Group JV in Mumbai. These TBMs were recently used on Delhi Metro’s new Pink Line and have since undergone extensive refurbishment in order to fulfill a section of highly weathered ground on contract UGC-05.
When complete, Mumbai Metro’s much anticipated Line 3 will be the first underground metro line in the city. The 33.5-km long line will connect Cuffe Parade business district in the far south to the Santacruz Electronics Export Processing Zone (SEEPZ) in the north-central with 26 underground and one at-grade station.
Construction of the line is divided into seven tunnel-and-station packages that were awarded to five contracting joint ventures in 2016. These five contractors will deploy a total of 17 TBMs with TERRATEC being the lead TBM supplier on the project with a 37% market share.