Milestone breakthrough for Malaysian water tunnel
2 May 2013The first of three 5.23m main beam Robbins TBMs broke through at the Pahang Selangor Raw Water Tunnel on 22 March 2013. The breakthrough is a significant step towards the completion of the longest tunnel in Southeast Asia, a 44.6km water transfer route from the states of Pahang to Selangor.
Many challenges were overcome by the TBM and its continuous conveyor system on the 11 km run, including blocky rock, over-break, power outages, extremely high rock temperature and water inflows. Robbins field service has worked closely with the contractor, a joint venture of Shimizu Corporation, Nishimatsu Construction, UEM Builders, and IJM Construction (SNUI). Despite the variable conditions, the TBM maintained strong advance rates of 475m per month on average, Robbins stated.
Various methods of support were used during boring, the primary being near-zero rebound fiber mortar. The Pahang Selangor project marks the first time that this method has been used outside of Japan.
"This is a day we all look forward to in the tunneling industry," said Andy Birch, field service manager, Robbins. "It's a good feeling when you get through all of the hard work and eventually break through. I'm very happy for this joint venture, and they seem very happy too."
The two remaining 5.23m machines are currently boring respective 11km runs, and are on schedule to meet inside the tunnel in autumn 2013. Upon completion, the tunnel will transfer 27.6cum of water per second to a new treatment plant. The drinking water will supply about 7.2M people for project owner KeTTHA (Malaysian Ministry of Energy, Green Technology, and Water).
