The first of seven Terratec TBMs being used on Mumbai Metro’s Line 3 project in India has broken through on its inaugural drive.
TBM manufacturer Terratec joined workers from J. Kumar - China Railway No. 3 Engineering Group (CRTG) JV to celebrate the breakthrough of a 6.68m diameter the dual-mode hard rock TBM boring for Mumbai Metro Rail Corporation (MMRCL) Line 3 project in India.
The machine is one of three new Terratec dual-mode TBMs being used by JV to excavate portions of the line’s 4.94km-long twin-tube tunnel and 4.45km-long twin-tube tunnel from Dharavi Station to the CSIA International Airport.
According to the manufactories the single shield TBM is equipped to operate in either open or closed mode in the predominantly fresh and slightly to moderately weathered Basalt and Breccia expected on the project. The hard rock cutterheads are mounted with heavy-duty 17” disc cutters, which are interchangeable with ripper tools, and feature large bucket openings that provide a 10% opening ratio, the firm said
In addition to the three new hard rock TBMs have also been supplied, as well as two re-manufactured 6.61m diameter mixed/rock Earth Pressure Balance Machines to the JV.
Watch a video of the break through below.
A further two new 6.68m diameter dual-mode hard rock TBMs are being used by the Hindustan Construction/Moscow Metrostroy JV to build the 4.049km-long twin tunnels. Both machines were deployed from the Chhatrapati Shivaji Terminal (CST) TBM launch shaft and are currently mining towards the Mumbai Central Station TBM receiving shaft, having now completed 3.7km of tunnel with progress rates of up to 525m per month.
In total, the seven Terratec machines have mined 9,462m (42%) of their planned drives to date.
When complete, Mumbai Metro’s Line 3 will be the first underground metro line in the city. The 33.5km-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 stations.
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 on the project.