Joint venture contractors SNUI, formed of Shimizu Corporation, Nishimatsu Construction IJM and UEM Builders, are celebrating breakthrough on the 44.6km long Pahang Selangor Raw Water Tunnel in Malaysia.
The breakthrough of the third Robbins Main Beam tunnel boring machine on the project marks successful completion of what is believed to be the longest tunnel in southeast Asia.
The tunnel is being built for the Malaysian Ministry of Energy, Green Technology, and Water (KeTTHA), drawing water from the Semantan river in the rainforests and taking it into Kuala Lumpur to address projected shortages for domestic and industrial use.
The 5.23m diameter tunnel was bored through the Titiwangsa mountain range under cover as high as 1,246m and below geothermal features including hot springs. Tunnelling conditions includes granite with a universal compressive strength of 200MPa, multiple fault zones and quartz dykes.
To cope with the ground conditions, all three of the Robbins TBMs were equipped with custom back-loading cutterheads and durable large diameter cutters. The highest production rate achieved on the project was 49m in one day and 657m in one month.