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. Against this background, this paper presents a survey conducted at the Norwegian Geotechnical Institute at 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 the 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, while 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.