Numerical investigation on the influence of cutting parameters on rock breakage using a conical pick

Abstract

To comprehensively understand the effects of roadheader cutting parameters on rock breakage, this paper conducts a numerical investigation of rock vertical indentation tests using a conical pick, utilizing the discrete element method (DEM). Three crucial cutting parameters, including cone angle, attack angle, and cutting depth, are analyzed as independent variables to elucidate their impact on rock breakage characteristics, such as peak cutting force and specific energy. The research results indicate that the ultimate failure of rock is primarily caused by the accumulation of microcracks from each local fracture, predominantly governed by tensile failure. As the cone angle increases, both the peak cutting force and specific energy exhibit a monotonic upward trend, while the maximum stress at the tip of the conical pick shows a fluctuating pattern. To achieve a balance between cost effectiveness and efficient rock breakage, an optimal cone angle range of 55° to 100° is recommended. The peak cutting force and specific energy decease exponentially as the attack angle increases, with an optimal range of 70° to 90°. Under continuous cutting conditions with a fixed total length of 60 mm, the average peak cutting force increases with cutting depth, while the average specific energy initially decreases and then increases, identifying an optimal cutting depth of 20 mm. These findings have significant engineering implications for optimizing the cutting parameters of roadheader to enhance the efficiency of mechanized excavation.