Solar power provides a clean and cost-effective energy source and is key in the transition to clean energy. The construction of solar farms in Australia has increased significantly, including Western Australia, and is expected to continue in future. Renewable energy is preferred in terms of sustainability and energy security, especially for industrial and resources projects. Solar trackers are rising in popularity due to benefits in increased energy production, cost effectiveness and sustainability. Foundation geotechnical design for solar trackers generally involves large areas and thousands of foundations (mostly piles). Basic design methods generally focus on a simple approach centred on saturated soil mechanics. This presentation will discuss specific issues to be considered in the design of solar farm foundations, from site investigation aspects to effects of extreme weather conditions and climate change, dealing with reactive soils, impacts of ULS loadings (wind and flooding) and soil-structure interaction aspects. Lessons learnt from the study of problematic projects will be shared.

Biography

Hugo Acosta-Martinez is a Technical Director – Geotechnical at BG&E Resources. He has more than 25 years of consulting experience, mainly in transport and resources infrastructure. He has been involved in numerous renewable energy projects involving solar and wind across Australia.

In his current role, Hugo provides technical leadership and independent verification on projects across the country. As a passionate advocate for inspiring the next generation of geotechnical engineers, Hugo is involved in mentoring young and emerging professionals, and has previously served as the National Chair of the Australian Geomechanics Society (AGS). With strong links to academia, Hugo is also a regular peer reviewer of leading geotechnical engineering journals and actively participates in forums that promote industry-academia collaboration.

Offshore wind will play a key role in the diversified sustainable energy portfolio into the future. Offshore wind is an established industry overseas, with a generation of experience in the North Sea region. Australia does not yet have a single turbine in the water, but momentum has been building significantly with the regulatory framework coming into effect, some states announcing targets, offshore renewable energy infrastructure areas being declared, and a large number of applications submitted for the first feasibility licences. This presentation draws on examples to highlight how local geotechnical engineering expertise has already influenced offshore wind projects half a world away, as well as providing a snapshot of substantial ongoing research activity and collaboration.

Biography

Britta Bienen is a professor of offshore geotechnical engineering at the University of Western Australia. Her research focuses on foundation and anchoring solutions for offshore wind turbines, underpinned by centrifuge and numerical modelling to develop practical prediction methods. The 2020 Australian Academy of Science John Booker medal recipient is also actively involved in the development of international guidelines (ISO, InSafeJIP, J-REG JIP) and currently serves on the Australian Research Council College of Experts.

Outcomes of a tailings slope stability benchmarking exercise

Recent tailings storage facility (TSF) failures due to slope instability have spurred greater scrutiny of TSF stability assessment. The TAILLIQ project conducted a Slope Stability Benchmarking Exercise, focusing on analyzing the stability of an idealized TSF slope with a rising phreatic surface in a dormant TSF. Participants had to predict the level at which slope failure would occur in two scenarios: sandy (Scenario A) and silty (Scenario B) tailings. The data for these scenarios was based on the Fundão and Cadia TSF failure reports. Results varied widely, with some predicting no failure and others suggesting instant failure without significant phreatic rise. Scenario A results highlighted a gap in understanding phreatic-triggered instability in TSF slope analysis.

Determining in situ degree of saturation in tailings: Current methods, uncertainties, and emerging technologies

Determining the in situ degree of saturation in tailings can be important for various analyses, with two particular cases being arguably of greatest importance: (a) tailings deposited in arid environments where air drying is promoted, resulting in unsaturated tailings and (b) filtered tailings deposits. In both cases, establishing what extent of the tailings deposit is unsaturated and the degree of saturation within the unsaturated portion of the tailings can have a significant impact on engineering analyses such as stability and liquefaction assessments. Despite the importance of inferring in situ degree of saturation, the currently available techniques suffer several limitations, uncertainties, and practical difficulties. This presentation summarises the current state of practice with respect to inferring in situ degree of saturation, then outlines work underway to verify the use of nuclear magnetic resonance (NMR) for this application in tailings.

Biography

David is a Research Fellow at The University of Western Australia.  He was 20 years’ experience in the design, in situ and laboratory characterisation, and analysis of tailings and tailings storage facilities.  His area of focus is on improving laboratory and in situ methods to characterise tailings behaviour.