DECEMBER SAW the first breakthrough of one of two TBMs being used on the SMART (Stormwater Management and Road Tunnel) project in Kuala Lumpur, Malaysia.
The 13.2m diameter mixshield slurry TBM completed the 737m drive in 24 weeks. A joint venture of Mott MacDonald and Malaysian firm SSP Consultants is supervising construction of the tunnel, which involves two TBMs working in opposite directions from the middle of the alignment.
SMART will divert floodwater away from the confluence of two major rivers running through Kuala Lumpur, with its central 3km section doubling up as a two-deck motorway to relieve traffic congestion in the city centre.
The 9.7km long, 11.8m internal diameter tunnel will work on a three mode system. In mode one it will act simply as a motorway tunnel. Moderate storms will activate mode two.
This will divert floodwater into a bypass tunnel in the lower section of the motorway tunnel, which will remain open to traffic.
During the once or twice yearly heavy storms, a switch will be made to mode three, closing the tunnel to traffic and using its full 3M. m 3capacity to divert increased flows.
Mott MacDonald carried out detailed design of the tunnel for the MMC-Gamuda JV which is building the scheme.
The highway section is due to be completed this year, with the bypass tunnel and associated works finished in 2006.