DTSS Tunnels

Overview

In DTSS Phase 2, the existing tunnel system will be extended to serve the western part of Singapore. The deep tunnels will convey used water by gravity to Tuas WRP for treatment. The tunnels will be constructed via 5 contracts.

View enlarged version >> DTSS Map

Tunnels Contract

Contract	Description
T-07: ED.Zublin AG, Singapore Branch	Consists of 3.5m and 6m diameter tunnels running primarily along Pan Island Express way and Ayer Rajar Expressway respectively. It also features the largest Odour Control Facility (OCF) that treats odourous air before it is released.	9 Shaft 4 Tunnel Boring Machines 12 km Tunnel Distance
T-08: Penta-Ocean Koh Brothers JV	Consists of a 6m diameter tunnel for domestic used water, which under-crosses the sea with the longest drive attempt at about 2km. It is also the only contract featuring an industrial used water tunnel about of 3.3m and 4m diameter along Pioneer Road.	10 Shafts 4 Tunnel Boring Machines 10 km Tunnel Distance
3T-09: Leighton Contractors (Asia) Limited (Singapore)	Only contract that has one common size Tunnel Boring Machines (TBM) (6m diameter) throughout its entire length and runs along the Ayer Rajah Expressway.	7 Shafts 3 Tunnel Boring Machines 8 km Tunnel Distance
T-10: Nishimatsu Construction Co	Only contract which uses the Earth Pressure Balance type TBM (the West Coast TBM) while all others utilise the slurry type TBMs. It comprises TBMs of 3.5m, 4m and 6m in diameter that runs mainly along Clementi Road, Farrer Road and Ayer Rajah Expressway respectively. It also features the deepest shaft across all contracts measuring 66m deep that is equivalent to a 23-storey building.	9 Shafts 3 Tunnel Boring Machines 8 km Tunnel Distance
T-11: Shanghai Tunnel Engineering Co (Singapore)	Marks the starting point of the tunnels and therefore, the shallowest under DTSS Phase 2. It runs mainly along Keppel Road and Telok Blangah Road. It features the most number of TBMs and shafts pf varying diameters, including an under sea crossing T-11 comprises TBMs of 3m and 3.3m in diameter, the smallest TBM used in DTSS Phase 2.	15 Shafts 5 Tunnel Boring Machines 12 km Tunnel Distance