Rapid Robbins Main Beam Reaches Record Production in Mumbai

Deep below Mumbai, a Robbins 6.25-m (20.5-ft) diameter MainBeam TBM is excavating for the 8.3-km (5.2 mi) Mumbai Water Tunnel.

The hard rock machine, for the joint venture contractorUnity-IVRCL, has been reaching impressive advance rates, including a recentrecord-breaking rate for tunneling in India. In October 2013, the TBM turned in 870.16 m (2,855 ft) inone month. The rate overturned a previous record at Kishanganga for a SELI TBMthat advanced 816 m (2,677 ft) in November 2012. 

The Robbins machine achieved the impressive advance rate inthe size class of 6 to 7 m (19.7 to 23 ft) TBMs. Robbins field service site managerLeif Schmidt felt that good cooperation played a large part in the projectsuccess: “We have a great machine and a great client that is making everyeffort to do daily maintenance and cutter inspection on the TBM, with adedicated 4-hour shift per day.” 

The achievement is especially notable considering the 109-m(357-ft) depth of the launch shaft. At that depth, the sheer amount of cover,heat in the tunnel, and time to lower materials to the machine are all factorsthat could potentially affect advance rate. Despite these challenges, themachine has performed exceedingly well. “[The machine’s] performance is good;we would recommend Robbins machines for hard rock boring,” said Unity generalmanager Pravin Titare.

Difficult ground conditions have also been an addedchallenge, including hard basalt rock, fractured ground, and water inflows.Although the machine is currently working in stable ground, tough geology wasencountered in early 2013. On thistopic, IVRCL general manager Bipin Arey said, “Our team has resolved theproblem, and the [Robbins] crew helped us strengthen the affected portion ofthe tunnel.”

The latest record isn’t the first set by the rapid RobbinsTBM. In December 2012, the machine set an Indian record of 57.4 m (188.3 ft)per day. The machine has also had a best week of 252.6 m (828.7 ft). “Highadvance rates are expected to continue for the duration of the project,” said RobbinsIndia managing director Kapil Bhati.

Once the tunnel is completed, it will provide Mumbai’sapproximately 20.5 million residents with a consistent flow of clean drinkingwater, even during the seasonal monsoons that contaminate the city’s waterresources.

This article was provided by The Robbins Co.

Contact Information:

Desiree Willis

Technical Writer

Email:willisd@robbinstbm.com

Direct: 253.872.4490

TheRobbins Company

29100 Hall Street

Solon, OH 44139

USA