Numerical Modeling of Cuttability and Shear Behavior of Chisel Picks.

The main purpose of this paper is to predict the rock cuttability by considering the peak cutting forces and analyze the shear behavior of chisel picks by numerical simulations on the basis of theoretical and numerical studies. Numerical modeling studies were carried out as two main parts using PFC3D. In the first part, triaxial compression test was modeled on soft and hard rocks at various confining stresses. In part two, a chisel pick was numerically simulated and advanced on artificially generated soft and hard rocks depending on different cutting parameters. Then, the variation of peak cutting forces with the rake angle and cutting depth was monitored by modeling unrelieved rock cutting tests. The simulation results were compared with the results of theoretical cutting mechanisms. In conclusion, it is found that reasonable relationships exist between two predictive methods. In addition, the effects of rake angles on the shear strength were analyzed using Nishimatsu's cutting model. The variation of shear angle during rock cutting was also examined. As a result of numerical studies, it is found that the theoretical formula proposed by Nishimatsu for the estimation of peak cutting forces and shear strength is mainly suitable in negative rake angles of chisel picks and in hard rocks. Furthermore, the shear planes of the microcracks in PFC3D were monitored and the shear angle was found to be ranging between 20° and 35°. These results were also verified by modeling of triaxial tests at different confining pressures. [ABSTRACT FROM AUTHOR]