## 4 Conclusions
For example, establishing a database of worn disc cutters would allow for the systematic monitoring of disc cutter wear under various tunnel conditions. This would facilitate data-driven decision making and enable the development of targeted maintenance strategies. Furthermore, with access to such data, material development for disc cutters could be optimized by focusing on the most common forms of wear. By adjusting material properties to reduce the frequency of these wear patterns, engineers can improve the durability and performance of disc cutters, ultimately increasing the overall efficiency of tunnel construction. Although this study is based on established methods, a novel application of close-range photogrammetry specifically tailored to TBM disc cutters is presented. As far as the authors are aware, this precise method for quantifying the wear of disc cutters by creating a dense point cloud and a three-dimensional model and then comparing it with reference profiles has not yet been used in this context before. This innovative approach enables a detailed analysis of volume and mass losses and provides a comprehensive insight into the extent of wear of the disc cutter. As this study presents the results of a single case study, it is important to recognize that the generalizability of these results may require further validation and testing in a broader range of conditions. Although this research provides valuable insight and forms a basis for evaluating the wear of disc cutters, it may not be directly applicable to all TBM operations, geological conditions, and cutter materials. In order to improve the generalizability of the results presented in this study, future investigations could repeat this study on several TBM projects with different geological formations, operating parameters, and disc cutter materials. Comparative analyses and validation in different scenarios could provide a more solid understanding of the wear patterns and evaluation methods for disc cutters and ensure broader applicability and the generalizability of the results. The aim of future work is to build on the results of this study to investigate other worn TBM disc cutters and comprehensively compare their wear patterns on a larger scale, considering geological variations and TBM boring parameters. Conceptualization, B.J. and A.P. ; methodology, B.J. and A.P. ; validation, B.J. and A.P. ; formal analysis, B.J. and A.P. ; investigation, B.J. and A.P. ; resources, B.J., A.P. and G.V. ; writing--original draft preparation, B.J. ; writing--review and editing, B.J. and A.P. ; visualization, B.J. and A.P. ; supervision, G.V. ; project administration, B.J. and A.P. ; funding acquisition, G.V. All authors have read and agreed to the published version of the manuscript. This research was funded by the Slovenian Research and Innovation Agency (ARIS) under grant number P2-0268 (B). The APC was funded by the ARIS Research Program, P2-0268 (B). Not applicable. Data Availability Statement: The raw data supporting the conclusions of this article will be made available by the authors on request. The authors would like to thank the Faculty of Natural Sciences and Engineering of the University of Ljubljana for administrative and technical support. The authors would also like to thank the company Braumann Tiefbau GmbH for providing materials for the experimental part of this study. The authors declare no conflicts of interest.