Numerical investigation on rock-breaking performance and arrangement optimization of disc cutter with miniature spherical inserts.

The cutter with insert teeth is a critical tool for TBM rock-breaking and has been widely applied in transportation and mining tunnel construction. The arrangement of insert teeth is a key factor influencing rock-breaking performance and load characteristics. However, conventional large-insert designs suffer from stress concentration and severe tooth failure in hard rock conditions, necessitating a new approach to tooth arrangement. To address this issue, this paper investigates the rock-breaking performance of disc cutters with miniature spherical inserts (CST). A three-dimensional numerical model for CST rock-breaking was established using the finite element method and validated against linear cutting experiments. Using this model, the influence of three insert arrangement patterns (three-row staggered, two-row symmetrical, and two-row staggered) on rock fragmentation performance was systematically analyzed, followed by a parametric study on the coupled effects of insert height (2.5-4 mm) and tooth count (120-192). The results show that the three-row staggered arrangement achieves the largest rock-breaking volume (1721 mm3) and the lowest vertical force (44.1 kN) among the tested configurations, while the two-row staggered arrangement exhibits the lowest specific energy (263.6 J/mm3) and the smallest rolling force (2.23 kN). For the granite investigated (UCS = 105.25 MPa) under the present test conditions (penetration depth of 5 mm, tooth count of 120-192), the insert height of 3 mm yields the lowest specific energy. The research findings reveal the influence patterns of insert arrangement and structural parameters on rock-breaking performance, providing a theoretical basis for the structural optimization and engineering application of cutters with inserted miniature spherical teeth.