First steps in the development of standardised processes for life cycle assessments of geotechnical works

Despite geotechnical works contributing considerably to the environmental impact of buildings and infrastructure, the application of life cycle assessments (LCAs) in geotechnical engineering still needs to be developed and matured. This paper presents a scenario analysis of an excavation in a typical Norwegian geology. For three excavation depths, different design solutions were derived varying the length of the supporting wall and the amount of soil stabilisation within the excavation. The cradle-to-site impacts of the different solutions were then evaluated through a LCA. Global warming and acidification potentials were compared for the different design choices in parallel with an estimate of the respective solution’s costs and different functional units were considered. The study shows that, for excavations in the chosen setting, most emissions are caused at product stage and the environmental impact related to the excavated volume or to the additional floor space created underground increases with excavation depth. It emphasises that different impact categories need to be considered to get a full picture of environmental impact. Simple to use LCA tools can provide a direct comparison of different potential solutions. Shifting the focus from minimising cost to minimising environmental impact will likely lead to different design decisions for geotechnical works.