Sustainability in geotechnical engineering – what does it mean and why does that matter?

The aspiration to act in a more sustainable manner has become a guiding principle across many aspects of life. Yet, sustainability is still often perceived as poorly defined, and there are diverse opinions on what the implications of sustainability for the everyday practice of geotechnical engineers are. On this background, this paper presents a survey conducted at the Norwegian Geotechnical Institute (NGI) in the beginning of 2021 that engaged a group of geotechnical engineers with the fundamental question as to how the concept of sustainability relates to geotechnical engineering. The Q-methodology, a mixed method approach, was applied to analyse different perspectives on sustainability in geotechnical engineering as inferred from the survey results. Three distinct perspectives were revealed that have a focus on (a) striving a balance between human action and nature, (b) mitigating adverse impacts of geotechnical projects, and (c) reducing resource use. Two of the perspectives considered the development of sustainability assessment tools as the most relevant means of working towards sustainable geotechnical practices whilst the third perspective considered multidisciplinary collaboration and research as more important. Reflection on these perspectives can help the development of future tools and strategies, provide a direction for future research, and contribute to a more sustainable geotechnical engineering practice.