Incorporating Life Cycle Assessment into Tunneling Technologies: Environmental Performance of TBM and ADECO–RS Methods

The article presents a quantitative analysis of the influence of selected material and structural parameters on the results of the life cycle assessment of a tunnel lining. The aim of the study was to evaluate the potential for reducing environmental impacts by decreasing the amount of concrete and reinforcing steel or by modifying the concrete mix composition. The analysis was conducted for two tunneling technologies: TBM and ADECO–RS (14 variants in total). The results indicate that concrete is the dominant factor shaping the environmental impact of the reinforced concrete lining, while reinforcing steel plays a supplementary role, depending on the adopted material variant (4–19%). Despite structural differences, both technologies show a similar level of environmental impacts, which confirms the need for full life cycle analyses and highlights a significant optimization potential within each technology. In the ADECO–RS method, increasing the concrete class did not contribute to reducing environmental impacts, whereas in the TBM method, the use of higher-strength concrete compensated for its higher unit impact by reducing the volume of structural materials. Differences in rankings between indicators confirm the relevance of a comprehensive, multi-criteria analysis in environmental impact assessment.