Metro Tunnel Early Works

Borehole geophysical surveys, detecting and verifying pile removal to ensure clear tunnel alignment for Melbourne’s $11B Metro Tunnel project

Make way for the Metro Tunnel

The $11 billion Metro Tunnel will deliver twin nine-kilometre tunnels and five new underground stations at Arden, Parkville, CBD North, CBD South and Domain, creating a new dedicated pathway through the city for two of Melbourne’s busiest rail lines.
The John Holland KBR Joint Venture have been appointed as Managing Contractor for the Metro Tunnel Early Works, the first package of works that includes:
■ The relocation of power, drainage, gas, water, sewer and telecommunications services.
■ The construction of two access shafts in Franklin Street and A’Beckett Street.
■ Major site preparation works including land clearing, property demolition, temporary relocation of monuments and tree protection and removal across all precincts.

Detection of left in piles

As part of the Early Works package, SIXENSE have been asked by the John Holland KBR JV to conduct a borehole geophysical survey to detect existing obstructions along the alignment of the TBM at North Melbourne Station. According to historical records, several abandoned or working foundations were expected at this location, next to the TBM launching box.
■ Several Hy-Tech piles and Franki piles have been removed and required a confirmation of the completeness of the removal process.
■ A former Sump Pit that was suspected to be founded on piles had to be investigated.
■ In addition, the whole TBM alignment had to be checked for other existing obstructions at the North Melbourne precinct.
The results of the survey helped the main contractor to remove the obstructions in due time.
The geophysical survey was repeated after all removal works were duly completed and did not reveal any strong significant anomalies. Based on these last geophysical results all the removal works were considered complete.