Sustainability assessment of conventional tunnel excavation: Analysis and results

The environmental footprint of transport infrastructure projects is largely shaped in the early project stages. In particular, the design decisions regarding the route selection of roads/ tunnels have a significant impact on the amount of construction materials used, the construction and tunnelling process, the life cycle maintenance requirements, and much more. Early integration of sustainability assessments seems to be an effective way to support sustainable construction and decision‐making processes. In tunnelling, the evaluation of infrastructure projects is usually a very challenging process due to the high level of complexity and numerous interdependencies. For this reason, assessment tools are currently being investigated to enable more efficient quantifications in the future. This study deals with the life cycle assessment (LCA) of conventional tunnel excavation using the New Austrian Tunnelling Method (NATM). Typical geological conditions and excavation classes are examined, and the environmental impacts are presented for a typical regular cross section. The resulting benchmark values determined per tunnel kilometre are intended to contribute to an integral and life cycle‐oriented approach and to further simplify sustainability assessments of tunnelling projects in early project stages.