Singapore DTSS Phase 1
2001 – 2005

From 2001 to 2005, five EPB Shields from Herrenknecht excavated more than 28 kilometers of tunnel in total for the expansion of the sewage network in the city state of Singapore. Altogether, the first expansion phase of the Deep Tunnel Sewerage System (DTSS) involved 48 kilometers of tunnel and was successfully commissioned in 2008. The tunnel system carries the collected wastewater to the Changi Water Reclamation Plant (WRP) in the east and the Kranji WRP in the north. In 2009, the large-scale project was designated "Water Project of the Year" at the Global Water Awards.

At depths of up to 50 meters below the city, the Herrenknecht EPB Shields handled extremely complex geological conditions. On the northern tunnelling sections T-01 and T-05 in particular, they encountered both hard rock with 200 – 300 MPa in places as well as heterogeneous and soft ground with groundwater pressure of up to 5 bar. The Herrenknecht engineers had adapted the TBMs specifically for these conditions. For example, for this reason the hard rock cutting wheels had a low opening ratio and were equipped with disc cutters instead of cutting knives.

After their tunnelling successes in the first phase of expansion, in Phase 2 the contractors again relied on tunnelling technology from Schwanau: for a total of almost 50 kilometers of sewage tunnels they ordered 18 Mixshields and an EPB Shield with diameters between 3 and 7.4 meters. Additionally, Herrenknecht’s mechanized shaft sinking technology VSM will be used in Singapore for the first time as well as a total of eleven separation plants.

Data Sheet

Country, Location

Singapore, Singapore


2001 – 2005




Soft ground
Heterogenous ground
Sandy clay, clayey sand, granite, slightly to completely decomposed granite, silt, sandstone

Tunnelling length

28,014 m

Machine Data

2x EPB Shield:
Diameter: 4,880 mm
Lining method: Segmental lining
Cutterhead power: 1,500 kW
Torque: 1,960 kNm

1x EPB Shield:
Diameter: 7,200 mm
Lining method: Segmental lining
Cutterhead power: 1,200 kW
Torque: 6,084 kNm

2x EPB Shield:
Diameter: 4,450 mm
Lining method: Segmental lining
Cutterhead power: 1,250 kW
Torque: 1,731 kNm

Your contact person Contact us

Steffen Dubé President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.