Desiree Willis, Technical Writer, The Robbins Company
- The second in a trio of 5.2m (17ft) diameter Robbins main beam TBMs has started its long journey near Malaysia's capital Kuala Lumpur.
Ceremonial launch for the project's first of three Robbins TBMs
- The three machines are delivered to the SNUI JV, consisting of Shimizu Corporation, Nishimatsu Construction, UEM Builders Bhd, and IJM Construction, to excavate the country's largest infrastructure project. The 44.6km (27.7 mile) Pahang Selangor Raw Water Tunnel will address projected water shortages due to the area's rapidly growing population.
- The project's first TBM was launched on November 10, 2010, and is advancing as scheduled while the total back up is being installed. A third machine will begin boring in March 2011. All of the machines are being assembled outside their particular adits, then 'walked' down a 6-10% grade to a NATM-excavated starter tunnel. Two of the machines are being launched with a shortened back-up configuration of ten decks and a temporary transfer conveyor, while the third machine, for logistical reasons is utilizing trucks for muck removal in the preliminary boring phase. Due to the adit configurations the remaining back-up decks and permanent Robbins continuous conveyors are being installed, after advancing about 100m (330ft).
The three TBMs were built at the Robbins factory in Shanghai
- During the initial stages of advance, the machines have achieved rates of up to 3.5m (11.5ft) per hour in hard, abrasive granitic rock up to 200MPa (29,000psi) UCS. Each High Performance (HP) main beam TBM is fitted with 19in back-loading cutters for effective excavation in the hard rock.
- The cutters are being carefully monitored in the hard, abrasive conditions using Robbins remote cutter monitoring systems, installed on each of the three TBMs. The wireless system allows the crew to plan cutter changes and keep track of cutter wear by recording several variables on each cutter, including cutter rotation (which is computed to percentage wear), temperature, and vibration.
- Each 19in face and gauge cutter is equipped with a sensor bolted inside the cutter housing, allowing raw data to be sent to a program display in the operator's cabin.
A blessing for the 5.2m diameter TBM before its long hard drive
- Tunneling is taking place beneath high cover conditions at up to 1,200m (3,900ft) below the Titiwangsa mountain range. The three tunnels, measuring 11.77km, 11.8km, and 11.3km (7.31, 7.33, and 7.02 miles) in length, will be supported with ring beams, rock bolts, and shotcrete, depending on the conditions. If unstable ground is encountered, invert thrust systems can be utilized to avoid gripping against the tunnel walls. The Precast concrete invert segments are being manufactured onsite.
- The Pahang Selangor Raw Water Tunnel, for the Malaysian Ministry of Energy, Green Technology, and Water, will convey raw water from the Semantan River in Pahang to the South Klang Valley area of Selangor State. Once complete, the tunnel will transfer 27.6m3 (7,300 gallons) of water per second to a new treatment plant. The drinking water will supply about 7.2 million people by 2013.
Malaysian raw water tunnel awarded - TunnelTalk, May 2009
Robbins trio to team up in Malaysia - TunnelTalk, Nov 2009
Record order for GIA on Malaysian water tunnel - TunnelTalk, Feb 2011
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