Effect of confining pressure, penetration depth, and cutting angle on the cutting mechanical characteristics of soft rock

Soft rock is a complex geomaterial characterized by significant plastic deformation under specific environmental conditions. This study employs the Particle Flow Code (PFC) numerical simulation technique to investigate the in-fluence of three distinct factors—confining pressure, cutter penetration depth, and cutter rake angle—on the mechanical properties of soft rock during cutting. The interrelationships among these factors are analyzed by cross-plotting the number of cracks, the magnitude of the cutting force, and the cutter displacement, while the force chains between particles are simultaneously monitored. The results indicate that the strength, size, shape, and number of cracks in soft rock are all altered by the cutting action. Utilizing a controlled-variable approach, this research examines the interactions and variations among different properties of soft rock, thereby providing insights to address challenges in practical engi-neering applications. For different lithologies, the influence of force on Acoustic Emission (AE) should vary. This study only investigated soft rock, and the threshold of force's impact on AE in soft rock was 15,000 N. When the force changes, this balance is disrupted. Above and below this force level, both the quantity and density of AE show significant variations. Under conditions of identical blade insertion depth and angle but different confining pressures, the AE scatter points appear more densely distributed without clear patterns, and no distinct thresholds for force or AE count boundaries are observed.