Located at the mouth of the Brisbane River, the project was delivered by Port of Brisbane Pty Ltd (PBPL). Pre-construction reclamation and ground treatment proceeded without delays and associated acid sulfate soils and groundwater were managed to meet regulatory requirements and minimise impacts to surrounding communities.
WSP served as PBPL’s lead geotechnical consultant for the project, which overlies thick, slowly draining layers of highly compressible and weak alluvial soils. Our primary involvement in the project was in geotechnical investigation, geophysical survey, analyses, design and monitoring for land reclamation and surcharge design to treat soils underlying the terminal building, roads and carpark areas, limiting post-construction and differential settlements. We also carried out investigations for the wharf structure.
Building on our local experience, we applied our understanding of the geology and geotechnical characteristics of the wider Brisbane River delta from previous nearby projects, as well as our expertise with problematic soft soils to investigate, assess and design earthworks for ground treatment. Our team of experts designed ground treatments to efficiently comply with the technical criteria, verified by instrumentation and monitoring. As the areas to be developed had tight settlement requirements, an understanding of the design parameters combined with sophisticated analytical methods was required through all phases of our work.
Sophisticated ground settlement modelling and optimised construction sequences were used to demonstrate that the ground treatment had no adverse impact on buried infrastructure crossing the site and in neighbouring properties. We also modelled differential settlement and lateral movements of the ground underlying the future terminal building. Issues with soft soil were overcome through suitable design of surcharge embankments with wick drains and high-strength basal reinforcement.
Adopting digital engineering solutions, the surcharge embankments for ground treatment were all designed in AutoCAD Civil3D, which enabled us to provide the client with a 3D model of the earthwork’s construction. This was a significant improvement on the traditional method of simply providing set-out points.
Additionally, a management and monitoring plan for acid sulfate soil and groundwater was created for PBPL to meet regulatory requirements and minimise environmental impacts.
Our expertise and long history of understanding the challenges of the geology underlying the site allowed us to offer efficient solutions, and at the same time maintain the project’s critical schedule, overcoming the risks posed by the thick, slowly compressible clays and acid sulfate soils at the site.
Since the completion of the project, we have continued to provide ongoing groundwater monitoring and geotechnical advisory services for auxiliary structures, utilities and assets to support the International Cruise Terminal.
* This work was performed by Golder professionals who joined WSP in an acquisition completed in 2021.
