ABSTRACT
Singapore is implementing the Deep Tunnel Sewerage System (DTSS) project as the long term solution to meet her needs in wastewater collection, treatment and disposal through the 21st century. Under this project some 48km of tunnels of diameters between 3.3m to 6m will be constructed. The tunnels will be excavated completely by tunnel boring machines. A total of 8 TBMs will be utilised for driving the 48km of tunnels. The tunnels have been let out in 6 design and build contracts. The tenders had attracted keen interest and participation from several international and local contractors. Awards of the 6 contracts were made between Dec 1999 and Mar 2000. Detailed design of the tunnels and shaft structures has been finalised. TBMs are being delivered and assembled on site. Driving of the tunnels will commence shortly.
