First of Two Mixed Ground Machines will begin boring this
autumn.
The first of two Slurry TBMs, a rebuilt 6.65 m (21.8 ft)
diameter machine, passed its factory acceptance on September 4, 2017 in
Singapore. The machine, fitted with a Robbins cutterhead and outer shields, is
destined for the Mumbai Metro Line 3 under contract UGC03 for the Dogus-Soma JV
(DSJV), and will begin excavation in late 2017.
The factory acceptance for a second 6.65 m (21.8 ft) diameter Slurry TBM
will be conducted by the end of 2017.
The on-time delivery of the first machine is just the
beginning of partnership that will span years.
“There are few companies in the international arena that are as
professional as Robbins. Robbins has
been very helpful to DSJV since the inception of the project and will be our
partners until the end of the contract. Robbins’ presence in India including
field service crews will be a great help for us in future,” said Mr. DV Raju,
Senior Vice President for SOMA.
The two machines will excavate parallel 3.5 km (2.2 mi) long
tunnels between Mumbai Central and Worli station sites, passing through three
intermediate cut and cover stations on the way.
Ground conditions consist of fresh to weathered basalt and breccia up to
100 MPa UCS with water pressures up to 3 bar.
The JV selected Slurry machines for their contract due to
the challenging ground conditions expected. “I have worked with Slurry TBMs on
similar geology globally. Slurry TBMs have real power and will suit the hard
rock geology of our Mumbai Metro contract 3. The water table and variable
geology, especially basalt of higher hardness, can be easily tackled by Slurry
TBMs,” said Mr. Tamay Sayin, Project Manager for DSJV. The cutterheads of the machines are fitted
with wear protection, wear detection bits, and Robbins 17-inch disc cutters for
the conditions. Grizzly bars will limit the size of boulders that can enter the
cutterhead to 250 mm (9.8 in). The
slurry systems includes rock crushers as well as abrasion-resistant plating in
high-wear areas.
The two TBMs are the first of a total of four machines being
provided by Robbins for the Mumbai Metro Line 3. Another two 6.65 m (21.8 ft)
diameter Crossover XRE machines will bore parallel 2.8 km (1.7 mi) tunnels on a
separate contract in 2018. “Mumbai Metro is one of the most prestigious metro
works in the country, and Robbins’ involvement in providing suitable machines
and associated services is an honor,” said Kapil Bhati, Managing Director for
Robbins India.
The 33.5 km (20.8 mi) long Line 3 of Mumbai Metro being
constructed by the Mumbai Metro Rail Corporation (MMRC) will consist of 26
underground stations and one at-grade station that will reduce heavy traffic
and rail congestion between Bandra and Churchgate areas of the city. A total of
17 TBMs are being procured to bore various sections of the tunnels, which will
be excavated at average depths of 15 to 25 m below the city. The entire line is
expected to be operational by 2021. For further
information please visit www.therobbinscompany.com
