Opportunities For Sustainable Geotechnical Engineering Practice: Two Case Studies From Australia

Geotechnical design elements are major consumers of energy and natural resources in civil and infrastructure projects. However, by applying appropriate levels of engineering and investigation, opportunities exist for more sustainable and resilient solutions that better understand the ground and geo-structure characteristics. This paper presents two project examples from Australia to illustrate such opportunities.

The first example is a residential complex development project proposed over a reclaimed land with underlying soft marine deposits in Sydney. An advanced site investigation revealed an opportunity to use preload and surcharge ground improvement methodology instead of the initially proposed extensive piled slabs. The earthworks were nearly completed, and geotechnical monitoring confirmed the design assumption. A project-specific earthwork specification was developed, considering the site won material characteristics and performance requirements of different zones of earthworks. Through collaboration between the designer and contractor, most of the site-won material could be used in specified zones of the earthworks on site, with or without treatment, without compromising the performance requirement.

The second example is a major new highway project, where value engineering led to a review of the concept design bridge foundations, retention systems, and site investigation results. Alternative structure types and amendments to the earthwork specification were recommended and justified by the local road authority. The proposed changes significantly reduced the construction cost and carbon footprint of the project, making it viable for ministerial approval. The paper presents a comparison of the CO emissions between the alternative solutions proposed and those initially considered, highlighting the contributions made in these projects to global and local sustainability goals.