<p>When tunneling in soil-rock mixed ground, inserted-tooth disc cutters exhibit extremely complex wear characteristics and mechanisms due to their unique surface topography and structure. This complexity poses significant challenges for wear evaluation and cutter management, thereby leading to premature cutter failure and unnecessary replacements. There is still a lack of comprehensive parameters and proper thresholds for evaluating inserted-tooth disc cutter wear. To fulfill this field of research, the present study investigated the wear characteristics of 208 inserted-tooth disc cutters replaced in Guangzhou Metro Line 18, 54 of which underwent 3D scanning to obtain the precise wear data. The wear data and characteristics were analyzed systematically to determine the dominant wear modes and reveal the wear development process. The results indicate that tooth drop (31.73%), uniform wear (12.50%), and side wear (4.33%) are the dominant wear modes of inserted-tooth disc cutters in soil-rock mixed ground. These modes are prone to developing into flat wear (12.02%) and structural damage (39.42%) if not inspected and replaced in time. Subsequently, multidimensional parameters including cutter tooth drop ratio (<i>CTDR</i>), cutter ring radial height wear ratio (<i>CHWR</i>) and cutter ring thickness wear ratio (<i>CTWR</i>) were proposed to quantify these wear modes comprehensively. Furthermore, a procedure for determining wear thresholds was proposed based on the analysis of wear characteristics from three typical wear stages, ranging from slight uniform wear to severe structural damage. The proposed parameters and thresholds were utilized in the cutter inspection and replacement for the remaining 200&#xa0;m of the tunnel. This application demonstrated their effectiveness in reducing the premature cutter replacement and preventing excessive wear development towards structural damage (approximately 20–30%), thereby extending the cutter service life (approximately 8–15%) and reducing the construction costs.</p>