Kruger J.,Thiess Pty Ltd.
Proceedings - Rapid Excavation and Tunneling Conference | Year: 2013
The Airport Link is a $4.8 billion project involving 15 km of tunnels and roads to relieve traffic congestion in Brisbane, Australia. The Jacked Boxes form a key component of the project where they allow the new motorway to pass beneath six busy railway lines. The Toombul junction site had a unique combination of ground conditions and technical challenges through which no similar scale jacked box operation had previously been attempted. The boxes measure a combined width of 38m, length of 65m and are one of the largest jacked box operations in the world. To enable the jacking of the tunnel, a wide range of ground improvement techniques were used during the works including jet grouting, canopy tubes, piling, geonails and tube á manchette grouting. The challenges that were overcome include soft clay ground conditions, 24/7 operating railway, low cover, man-made obstructions, strict settlement criteria and flooding from an adjacent watercourse. The boxes were successfully jacked into position during a continuous operation in 2011, with no disruption to the rail services. Source
Fong Y.T.,Thiess Pty Ltd.
International No-Dig Madrid 2014 | Year: 2014
The Gladstone Liquefied Natural Gas Project is a development in Queensland, Australia to convert coal seam gas into liquefied natural gas for export to global markets. The pipeline alignment had crossed the Narrows in order to be connected to Curtis Island where the processing and export facilities were located. Given the environmentally sensitive located of the crossing, several crossing methods were considered from concept till delivery of the project. Ultimately an innovative tunneling solution was selected for the crossing, which minimized environmental disturbance of the sensitive shore and near shore protected areas close to the Gladstone Harbour and Great Barrier Reef. Even with the crossing method selected there were several technical challenges overcome for example low ground cover, challenging geological condition, pipeline installation method and the requirement to meet corrosion protection for the pipeline. The most important of them all, the requirement to launch the tunneling machine within 12 months of feasibility studies had made engineering and design of the tunnel an extremely challenging task. This paper examines the whole crossing selection method from concept to execution. The author who was involved from concept to completion of the project will also discuss specific engineering difficulties and actual execution of the tunneling works. Copyright © 2014 ISTT. Source