WestConnex Stage 2 New M5 Motorway

LOCATION:  Sydney, New South Wales, Australia   |   OWNER:  Sydney Motorway Corporation
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The New M5 Motorway is Stage 2 of WestConnex, Australia’s largest integrated transport and urban revitalization project, and was delivered by Sydney Motorway Corporation on behalf of the New South Wales Government. The New M5 consists of twin underground motorway tunnels, 9-kilometers long (5.6 mi), which extend from Kingsgrove to a new St. Peters Interchange at the site of the old Alexandria landfill facility. The St. Peters Interchange gives motorists connections to Alexandria and Mascot, and connections to the future Sydney Gateway and M4-M5 Link. The New M5 twin tunnels also include underground connection points for the M4-M5 Link and the Southern Connector.

The New M5 Motorway project was designed and constructed by the CPB Dragados Samsung Joint Venture (CDS). Under a Design JV subcontract, McMillen Jacobs provided detailed design for excavation sequencing; and temporary and permanent support of the two-lane mainline tunnels, cross passages, breakdown bays, substations, portals, ventilation shafts and tunnels, and temporary access tunnels. The firm also provided Construction Phase Services.

McMillen Jacobs is responsible for delivering six tunnel design packages, procurement specifications, and the tunnel design criteria report. Four construction sites provide access to the mainline tunnels through tunnel declines. The project geology consists generally of sandstone overlain with shale. The tunnels were designed and excavated using SEM/NATM.* Excavation was almost entirely by roadheader.

The project faced a challenging timeframe and milestone dates within the design and construct (D&C) process. McMillen Jacobs started detailed design work of the New M5 tunnels in November 2015. Construction broke ground in July 2016 on the temporary works design packages: Kingsgrove Temporary Works, Bexley North Temporary Works, Arncliffe Temporary Works, and St. Peters Interchange. By early 2017, up to 19 roadheaders were in concurrent operation in the New M5 tunnels. Tunneling work and support activities (including transporting excavated material) operated 24 hours a day, seven days a week at some stages.


SEM/NATM: Sequential Excavation Method / New Austrian Tunnelling Method.