Rock breaking of conical cutter with assistance of front and rear water jet

• Different combinations of water jet and conical cutter were put forward.
• Models of rock breaking with assistance of front and rear water jet were established.
• The cutting force curves were established and compared with the experimental data.
• The shock waves of water jets at different positions and pressures were analyzed.
• The peak cutting force of conical cutter reduces by about 28–40%.

During the excavation of roadway or tunnel excavation in hard and abrasive rock, the conical cutter is subjected to high cutting forces and serious wear. Therefore, different combinations of water jet and cutter were put forward for this issue, and the damage models of rock breaking with a conical cutter under the assistance of front and rear water jet were established based on the SPH and Lagrange algorithm. By analyzing the dynamic processes of rock breaking with a single cutter under different cutting depths, the cutting force curves were established and compared with the experimental data, the simulation were proved feasible and effective. Then, the effects of rock breaking with the assistance of water jets at different positions and pressures were analyzed, and comparisons were conducted with the effect of rock breaking with a single conical cutter without water jet. The results show that: the numerical cutting force of rock breaking with a single conical cutter coincides well with the theoretical and experimental data. Compared with the peak cutting force of cutter without water jet, the peak cutting force of cutter with the assistance of the front water jet (FWJ) reduces by about 14–30%, and the reduction percentage decreases with the cutting depth, while, the peak cutting force of cutter with the assistance of the rear water jet (RWJ) reduces by about 28–40%, and the reduction percentage is almost not affected by the cutting depth. The effect of rock breaking with the RWJ is better than the FWJ, and the RWJ with the incline angle 5° is the best, the peak cutting force of cutter reduces by about 31%, 39%, 43%, 45% with the water jet at different pressures of 20 MPa, 40 MPa, 60 MPa, 80 MPa, respectively. The effect of rock breaking can be improved by increasing the pressure of water jet.