Mumbai, June 8 (IANS) The first Tunnel Boring Machine (TBM) for the 33.50-km-long Mumbai Metro-III corridor package, and the ninth in the overall project so far, has arrived in the city, a top official said here on Friday.
The TBM, Surya 1, will start tunnelling in the heritage areas of south Mumbai between Cuffe Parade to Hutatma Chowk soon, said Mumbai Metro Rail Corpoation (MMRC) Managing Director Ashwini Bhide.
One of the longest metro lines in the city, the fully underground Metro III will cost around Rs 23,136 crore, partly funded by Japan International Cooperation Agency through a soft loan of Rs 13,325 crore, and the rest by the central and state governments.
It will slash travel time between Cuffe Parade to Mumbai Airport by half and drive off around half a million vehicles per day from the congested roads, thereby saving over Rs 550 crore in fuel annually after it is completed by 2021.
The TBM, weighing over 700 tonnes, has a diameter of 5.8 metre and is 98 metre long, and after assembling its front and middle shields, cutter head, erector, screw conveyor and tailskin shield over a period of 30 days, it will be lowered from a launching shaft in Cuffe Parade using heavy duty cranes of 750 tonne capacity.
Imported from the Robbins Company, the US, it has been manufactured at its Shenyang, China facility, and will be deployed for digging two long tunnels below Cuffe Parade, Vidhan Bhavan, Churchgate and Hutatma Chowk Metro stations, she said.
It will use 4,086 tunnel rings to construct the tunnels with circular cross sections and will join the eight TBMs that are already boring underground in different parts of Mumbai for the metro mega-project.
The precast segments, essential for forming a concrete ring inside the tunnels, are already being manufactured at six different casting yards.
The entire project will require a whopping 37,879 segment rings which will be casted in 65 moulds imported from France and Korea and 33 per cent of the segments have already been cast so far, said Bhide.
“By August, all the 17 TBMs will be ready on ground to build the Colaba-Bandra-SEEPZ Metro III corridor. So far we have completed nearly four km of tunnelling, and with Surya-1, the work will be speeded up,” Bhide added.
While TBMs Krishna 1 and 2 of Package 4 have completed 1.6 km boring, TBMs Vaitarna 1 and 2 of Package 2 have completed 700 metre, TBMs Godavari 1 and 2 of Package 5 and TBMs Wainganga 1 and 3 of Package 7 have bored over one km totally.
Interestingly, Bhide said the MMRC has named all the 17 TBMs in the Mumbai Metro’s seven packages after the major rivers flowing in Maharashtra like Surya, Vaitarna, Tansa, Krishna, Godavari, Tapi and Wainganga.