Numerical investigation of rock breaking by a dish-shape cutter with advance slotting

A numerical model of rock breaking by dish-shape cutter wedge cracking assisted by advanced slotting was established by coupling the finite element method (FEM) and cohesive element method (CEM). The accuracy of the model was verified by uniaxial compression and cutter cutting rock experiments. The rock-breaking process of cutter wedge cracking was analyzed by combining the characteristics of thrust load and the ratio of tensile damage. The effects of the slotting feature and tool geometric parameters on the rock-breaking performance were studied. The results showed that advanced slotting can weaken the strength of rock, reduce the load of the cutter, and improve the rock-breaking efficiency. Shear failure was the main fracture mode of uncut rock extruded by the cutter, while tensile failure was the main fracture mode of extruded rock advanced slotting. The propulsion load of the cutter and the size of the rock fragment increased with increasing cutting thickness and inclination angle. The optimal values of cutting thickness and inclination angle of cutter were 30 mm and 40°, respectively. The load and specific energy consumption of cutter rock breaking decrease with increasing advanced slotting depth. However, the downward trend was no longer obvious when the slotting depth was more than 15 mm. The rock-breaking performance of the cutter increased with increasing radius, but the increasing amplitude tended to be constant when the cutter radius was greater than 70 mm.