Wiggins Island Coal Export Terminal – Reclaim Tunnels

Bonacci Infrastructure delivered the permanent works design for four kilometres of cut-and-cover coal reclaim at the Wiggins Island Coal Export Terminal (WICET) which was awarded as an alternative design. Key project challenges included:

• Highly variable stockyard loading / geotechnical conditions, including varying depths of consolidating clay which transitioned abruptly into rock. Finite element geotechnical modelling (including consolidation) was completed to determine the effects of variable coal stockpile loads on the tunnel.
•  The need for the tunnel to be watertight and highly durable, which resulted in a monolithic design solution which proved to be superior to more conventional precast systems.
• Stockyard temporary works, including the review of the 1250 tonne crane (LTL-1100 transi-lift) loading adjacent to the tunnels.

The tunnels were designed using in-situ concrete methods, with the geometry being tailored for a travelling form and reinforcing bar support jig.

The design of the tunnel involved extensive non-linear soil-structure interaction modelling that resulted in an efficient “fit-for-purpose” solution in very challenging soil conditions.