WestConnex M4-M5 Link

Engineering and Technical Opportunities

The M4-M5 Link is a significant infrastructure project connecting the new M4 at Haberfield to the new M5 at St Peters, Sydney, NSW. It is the last step before the completion of WestConnex.

The project consists of two stages:

Stage 1: Construction of the M4-M5 Link twin mainline tunnels between the M4 and M5 and stub tunnels to the Rozelle Interchange.

Stage 2: Construction of the Rozelle Interchange and Iron Cove Link; including an underground motorway interchange to City West Link and a bypass of Victoria Road between Iron Cove Bridge and Anzac Bridge, and links to the future Western Harbour Tunnel.


WestConnex M4-M5 Link


Acciona Samsung Bouygues Joint Venture (ASBJV)


Sydney, Australia

Time Frame

April 2018 – 2022 (Ongoing)


$3.20 Billion

Approach and Innovation

JDK’s streamlined approach to the project involved the systematic capture of geotechnical and geological information. Under the direction of the internal engineering management, our consultants have been involved in the following project aspects:

    • Geotechnical assessment and confirmation of ground conditions for support type design compliance
    • Permit to Excavate (PTE) and Permit to Trench (PTT) through ground conditions with high defect and at times weak rock mass
    • Review for shear displacement within roof bolt horizon
    • Geotechnical inspection and assessment of geological conditions of rock cuts, face roads and portals.
    • Geological defect mapping and monitoring and remediation
    • Rockfall prevention and remediation
    • Water seepage mapping for final fit-out

Value Added to Project

Our team was responsible for the professional interaction with relevant stakeholders and provided extensive geotechnical expertise to interpret the practices used to manage and control tunnelling risk.

JDK’s vast geotechnical expertise coupled with extensive stakeholder communication enabled the efficient capability of our deliverables. JDK was able to utilise industry best practices to ensure geotechnical risk was identified, captured and communicated. Precise inference of ground conditions within areas of geotechnical risk allowed the client to achieve the schedule.

All work was completed safely, within budget and on time.

Project Highlights