Client: Public Utilities Board
Main Contractor: Philipp Holtzman - SembCorp JV

Drilling: 130 holes, 35m long, 150mm Ø

Drilling of 150mm holes Ø pipes, for ground freezing pipes (89mm Ø).

Following a collapse in the cavern at the foot of the tunnel access shaft, the Main Contractor has decided to undertake ground freezing to stabilise the excavation for the installation of the Tunnel Boring Machine and it's back up train.

Picture credits to Patrice Ghelfi