Framework for whole life cycle assessment of geotechnical engineering projects

We developed an actionable framework for evaluating the environmental impacts incurred across the whole life cycle of geotechnical engineering projects suitable for practitioners and academics. This framework aims to establish best practices for geotechnical life cycle assessment (LCA) and facilitate the sustainable design of geotechnical projects. We consider the whole life cycle of such projects, including the following project stages: site investigation, construction, use, and end-of-service-life. The framework is appropriate for existing and future structures and cases where, for example, foundational support is needed or where geologic hazards (e.g. earthquakes) are a concern. This framework guides completing a geotechnical whole LCA, termed as a Geo-WLCA, following the ISO 14040 and ISO 14044 LCA standards. The framework builds on these generic standards to reflect the specific needs of the geotechnical sector. These include, for example, the definition of the key life cycle phases across a geotechnical project and of the LCA’s functional unit. To demonstrate the framework’s usability, we present a case study to evaluate the whole life cycle environmental impacts of a permeation grouting project for earthquake-induced liquefaction mitigation. From our results, we found that the construction stage of the permeation grouting project, specifically materials supply for the microfine cement grout and equipment operation, contributes significantly to the whole life cycle impacts. Further, we determined that site investigation activities account for less than 1.2% of whole life cycle impacts. This suggests that an increased scope site investigation program could provide a better understanding of the subsurface, thereby reducing design uncertainties without significantly affecting the environmental impact of a permeation grouting project.