Sydney F3 to M2 link (NorthConnex)

— Project Description:

The project would comprise the following key features: Twin motorway tunnels up to around nine kilometers in length with two lanes in each direction. The tunnels would be constructed wide enough for a third lane in each direction if required in the future. A northern interchange with the M1 Pacific Motorway and Pennant Hills Road, including sections of tunnel for on-ramps and off-ramps, which also facilitate access to and from the Pacific Highway. A southern interchange with the Hills M2 Motorway and Pennant Hills Road, including sections of tunnel for on-ramps and off-ramps.

— Description of Services:

The scope of engineering service for Geodata was to supply an experienced tunnel engineer to assist GLOBALINK JV with the preparation of the tender design for the M2F3 connection in Sydney, including necessary support from the head office of Geodata in Turin, Italy.
Specifically, the engineer supplied by Geodata should act as the TUNNEL DESIGN REPRESENTATIVE & COORDINATOR to ensure that the design should progress with a proper peer review.
As GHD was the Designer hired by GLOBALINK JV to prepare the tender design, the experienced engineer supplied by Geodata was expected to work with the GHD’s Principal Tunnel Engineers, Tunnel Engineering Geologists and others of the Design team.
From a pure technical point of view, the team of Geodata concentrated their efforts on the following aspects:

• Evaluation of the design in its main aspects accordingly with the Geodata international experience in similar works. 
• Critical review of the available information about the ground conditions from the prospective of 1) identifying the optimal construction method for the mined tunnel, caverns and ramps including that of ground improvement/treatment, 2) characterizing the ground with definition of ground property values for input to design, and 3) identifying the hazards (thus risks) associated with the design and construction of the works. 
• Optimization of the geometry of the excavations in the light of the elected, optimal construction method. 
• Optimization of the construction sequences of excavations as well as the extent of the ground improvement/treatment required, checking the stability of the excavations at various key steps, without and with support elements, through both simplified design analysis and numerical modelling. 
• Evaluation of the residual level of risks involved in the adopted solution with suggestion 
• On how to manage them during construction phase.

It is noted that the selection of the construction method including ground improvement technique and the optimization of the geometry and the construction sequence shall be done in close cooperation with GHD’s design team and the bidder, through exchange of ideas and meetings.