Malaysian raw water tunnel awarded
Malaysian raw water tunnel awarded May 2009
Paula Wallis, Reporter
The Shimizu lead consortium has secured the RM1.3 billion ($US 370 million) tunnel contract for the Pahang – Selangor Raw Water Transfer Project in Malaysia.
On May 4, the Ministry of Energy, Green Technology and Water awarded the project to the joint venture of Japan’s Shimizu Corporation and Nishimatsu Construction, each with a 30% stake and local companies IJM Corp and UEM Builders Bhd, each with a 20% stake in the consortium.
Existing tunnel

Tunnel alignment

Located in central Malaysia, the project is designed to alleviate future water shortages by conveying raw water from the Semantan River through a transfer tunnel to the Selangor/Kuala Lumpur region for domestic and industrial uses. Two lanes of 3m diameter pipeline each roughly 11.8km (7.3 mile) long will convey raw water from the Semantan intake and pumping station to the connecting basin and tunnel in Karak. From the connecting basin the raw water is transferred through the 44.6km long x 5.2m diameter (27.7 mile x 17ft) tunnel with gravity flow to an outlet connecting basin (Fig 1). The collected water is further distributed also via gravity and through pipelines to receiving basins of a planned treatment works contract. The outlet connecting basin and pipelines to the treatment plant are part of the treatment works. The tunnel includes the inlet connecting basin, inlet and outlet conduits and four adits.
Existing tunnel

Fig 1. Raw water tunnel scheme

The tunnel passes through the main central mountain range with elevations typically exceeding 1,200m (3,900ft) and will have a longitudinal slope of 1:1,900. Bedrock along the alignment consists of metamorphosed rocks of the Karak Formation for the initial 3.5km (2.2 mile) reach from the inlet. The remaining portion is in granites.
Tunnel excavation will be mostly by TBM with three TBMs completing a total of 35km (22 miles). Four conventional drill+blast headings will complete the remaining secitons. The portal zones of the long tunnel will be excavated using the sequential excavation method (SEM). The inlet and outlet conduits are designed as cut-and-cover type culverts of horseshoe shape with vertical walls. They will be 4.0m (13ft) wide x 4.7m (15ft) high.
Tunnel construction is anticipated to take five years with completion in 2013.
Ministry of Engergy, Green Technology and Water


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