Application of Pre-Grooving Assisting Conical Picks Cutting Hard Rock and Effects of Cutting and Kerf Parameters on Rock-Cutting Performance

Pre-grooving is an effective means of facilitating hard-rock cutting with conical picks, reducing pick wear, and improving rock-cutting efficiency. However, research on the effects of matching cutting parameters with kerf parameters on rock-cutting performance remains limited. Using granite with a strength exceeding 130 MPa, this paper establishes a model of rock cutting by conical pick by employing the discrete element method (DEM) and verifies the validity of the model by rock-cutting tests. Based on the DEM, the effects of cutting depth, kerf spacing, and kerf depth on mean cutting force, rock fragmentation volume, and specific energy of pick cutting rock are numerically investigated, and the response surface method is used to determine the significance of each factor for the respective performance indicators. The results show that both cutting depth and kerf depth affect the critical kerf spacing. When the kerf spacing does not exceed its critical value, mean cutting force and rock fragmentation volume increase with increasing kerf spacing, whereas specific energy decreases. Therefore, an excessively small kerf spacing is not conducive to increasing the rock fragmentation volume of the conical pick. Increasing the kerf depth facilitates rock breaking by the conical pick. Cutting depth has the most significant effect on mean cutting force, followed by kerf spacing. Cutting depth also has the greatest effect on rock fragmentation volume, followed by the interaction between cutting depth and kerf spacing, while kerf spacing and kerf depth also exert some influence. Specific energy is most strongly affected by kerf depth, followed by cutting depth and the interaction between cutting depth and kerf spacing. These findings provide guidance for the rational matching of cutting and kerf parameters in pre-grooving assisting conical picks cutting hard rock.