Deep Tunnel Sewerage System 2 T07, Singapore

Project type:

  • Utility tunnel 


  • Precast segments


  • Owner: Public Utilities Board
  • Contractors: Zublin Singapore
  • Precaster: Zublin Precast Industries Malaysia


The Deep Tunnel Sewerage System (DTSS) is a water management system that comprises a network of sewers that lead to two major tunnels (Phase 1 & 2). The network covers nearly all of Singapore and connects with three large water reclamation plants at the northern (Kranji), eastern (Changi) and western (Tuas) ends of Singapore, as well as with outfall pipes.

Part of the phase 2 tunnel is lined with precast segments reinforced with Dramix® 4D steel fiber concrete reinforcement.

The challenge

The total length of the tunnel is 12 km (7.5 mi) and has an internal diameter of 6 m (20 ft). One of the biggest challenges of this project, as is for any tunnel projects that deal with water and raw sewage, is to protect the lining from corrosion caused by bacteria, micro-organisms and gaseous fumes. In addition, the lining is also required to be as watertight as possible.


The solution

Designed with serviceability in mind and providing optimal crack control, Dramix® 4D steel fibers are specifically designed for durable and liquid-tight structures, making it the perfect reinforcement solution for this project. The precast segments use a concrete class of 60N/mm2.