Case study on jaw crusher rock breaking for slurry TBM using Tavares UFRJ breakage model and coupled CFD-DEM

To date, the transport and discharging of rock chips, considering single-particle breakage behavior in secondary breaking system, such as jaw crusher, remains under-explored. This paper uses the Qingdao Jiaozhou Bay Second Undersea Tunnel in China, as an engineering background and case study. A three-dimensional coupled model considering the rock particles breaking and slurry flushing behavior within the crushing box of jaw crusher was established using coupled computational fluid dynamics-discrete element method (CFD-DEM) approach. The breakage behavior of rock chips was described based on Tavares Universidade Federal do Rio de Janeiro (UFRJ) breakage model. The results revealed two key findings: first, the jaw crusher employs a hybrid rock-breaking mechanism that combines extrusion and impact crushing. Second, the slurry flushing inlet generates concentrated flow pathlines in the lower region of the crushing box. These flow pathlines direct rock particles toward the jaw crusher and intake screen, partially preventing particle aggregation and clogging. Meanwhile, the locations of reinforcing plates or abrasion-resistant layers are identified based on the severe wear and stress concentration areas of the equipment. Besides, a series of parametric investigations were performed to investigate the effects of operating parameters of jaw crusher. Lastly, the optimal operating parameters of jaw crusher were suggested. The findings of this study could provide references for addressing slurry chamber clogging during slurry tunnel boring machine (TBM) advancement in hard rock in similar future projects.