ABSTRACT
Life Cycle Assessment (LCA) is a multicriteria method for evaluating the potential environmental impacts across the entire life cycle of a system. The life cycle typically includes stages such as raw material extraction, manufacturing, transportation, use and end-of-life: recycling and/or final disposal. It has been implemented in recent years in the tunnelling and underground space field. However, in the case of mechanized tunnelling, current studies usually focus only on materials (segment lining, filling mortar…) and not the Tunnel Boring Machine (TBM) manufacturing or end-of-life scenario itself. Thorough considerations regarding TBMs must be carried out, especially given their now widespread use on construction sites and the specificities of the related construction method (a unique machine is dedicated to a given project with an EoL scenario, main installations could be required as for the treatment of waste slurry, the pre-casting of segments…).
This paper looks at how the LCA methodology can be used for assessing the potential environmental impacts of both TBM manufacturing and TBM tunnelling. Furthermore, it applies the methodology to part of a real-world construction project: the Mont Cenis base tunnel of the cross-border section of the Lyon-Turin railway line. Data collection was conducted in collaboration with both TELT and Herrenknecht. By leveraging industry partnerships, this study aims to provide valuable insights into the environmental assessment of TBM tunnelling and contribute to helping decision-making in the development of underground transport infrastructure.
