To address the challenges of wear resistance for shield cutterheads and cutters in high-abrasion sandy cobble strata, this study uses the Beijing Metro Line 19 tunnel Niujie–Jinrongjie section as an engineering case study. It employs the DEM to develop a crushable sandy cobble model, evaluate the stress characteristics of fishtail cutters, rippers, and scrapers, and analyze load distribution in the cutterhead and cutters—including underlying causes. Based on simulations, the study proposes and implements targeted wear-resistant designs for field application. The results indicate that the stress variation patterns of fishtail cutters, rippers, and scrapers with respect to time and installation radius are similar. The cutterhead’s opening distribution significantly influences the intensity of normal and lateral stresses. Caused by cutting resistance, high-stress loads in cutters accumulate at the cutting edge, while those in the cutterhead localize to the soil-facing side of its spokes. Meanwhile, hindered muck flow and cutting failure of gauge cutters also cause stress concentration in the cutterhead’s transition zones and outer side of the large ring. Adopting a DEM-based method that characterizes the stress of the cutterhead and cutters to develop targeted wear-resistant designs can effectively control the wear of cutters and cutterheads in in situ engineering. The rate of abnormal cutter damage was limited to merely 5.84%, while the observed wear of the ripper cutters remained consistently below the values predicted by the IHI empirical model. This study provides a scientific basis for wear-resistant design of cutterheads in similar high-abrasion strata.
Liu et al. (Fri,) studied this question.