Abstract:
The cutting efficiency in underground excavations relies on the optimum parameters of the
cutting tool and the cutting process. However, the optimization of the cutting tool design and the cutting
process is a challenge and requires knowledge about the tool–rock interaction. This paper aims to investigate
the tool–rock interaction using a rock cutting mathematical model. The confining pressure was considered
in the rock cutting model with conical cutters and the discrete element method was adopted to calculate
the dynamics of the rock breakage of this model. Graded particle assemblies were created, calibrated, and
compressed in the horizontal direction with a certain confining pressure. Afterwards, the initiation and
propagation of cracks during the rock cutting processes were recorded. A series of small-scale rock cutting
tests were also carried out to verify the numerical model. The analysis results demonstrate that: 1) the
confining pressure induced larger cutting force than that in the unconfined condition; 2) with increase of
the confining pressure, the rock failure mode experienced predominantly brittle to predominantly ductile
failure; and 3) there was a critical confining pressure/compressive strength ratio of 0.53 when the transition
of failure mode occurred.
