The Herrenknecht EPBM supplied to the project worked its way through complex ground conditions, including highly weathered granite. The TBM was equipped with 57 no. 17” double disc cutters and 56 scrapers. Overburden was 4m at the ends of the tunnel and 5m along most of the alignment.
Once it had completed the first drive, it was returned to the 24m-diameter launch shaft to begin the second.
Tiong Seng Contractors had to navigate a winding alignment with very little distance between the two tunnels and curve radii of 180m. Performances of up to 18m per day and 91m per week were achieved.
The project will expand the existing drainage system, the Stamford Canal, and reduce the chance and severity of flooding in the area.
