Comparative analysis of tunneling performance for conventional and atmospheric cutterhead under similar geological conditions: A case study of the Haizhuwan tunnel project

Cutterhead is the core component of the tunnel boring machine (TBM). In slurry TBM engineering, conventional and atmospheric cutterheads are usually associated with different cutterhead structure, cutter change mode and auxiliary system configurations, which may lead to different responses under complex geological conditions. To explore the tunneling performance and differences, this study presents a comparative field case analysis of two slurry TBM system configurations featuring conventional and atmospheric cutterheads in the parallel tunnels of the Haizhuwan Tunnel Project. First, the tunneling performance under four representative geological conditions was analyzed based on tunneling data, equipment modifications, and cutter failure characteristics. Subsequently, the Kruskal-Wallis test was used to compare the tunneling differences between the two machine configurations, with tunneling time per ring and construction time per ring taken as the main evaluation indicators. The results show that, under the investigated project conditions, in challenging environments, such as soft soil strata with poor formation stability, the atmospheric cutterhead configured system demonstrates better tunneling performance. In contrast, in hard rock strata, particularly under high rock hardness conditions, conventional cutterhead configured system exhibits superior tunneling performance. These findings provide practical engineering reference for slurry TBM equipment configuration and construction organization under similar geological conditions.