Experimental and Numerical Simulation Investigation on Rock Breaking for Granite with Laser Irradiation

To investigate the efficacy of laser as an auxiliary rock breaking technology and its compatibility with TBM (tunnel boring machine) tools, we conducted three experimental series with different laser power levels and scorching durations. Static tests showed that higher laser power led to greater rock-breaking depth. The relationship between laser power and kerf depth was linear for short irradiation times but followed a logarithmic trend for longer times. However, laser assisted by high-pressure gas blowing rock breaking showed a consistent linear increase in depth with rising laser power. Mobile laser rock breaking tests demonstrated decreased kerf depth with increased movement speed. Numerical simulations using a thermal-mechanical coupling model confirmed that longer laser scorching times led to more extensive internal cracks in rocks, primarily shear cracks, and reduced the force needed for hob rock breaking. This research suggested the feasibility of laser technology as a complement to TBM hobs for rock breaking. This study investigated the effects of laser power, irradiation time, high-pressure gas blowing and laser movement speed on laser irradiation breaking graniteBlowing high-pressure gas-assisted laser irradiation rock can improve kerf depth markedly.Laser irradiation rock induced mainly shear cracks and a minority of tensile cracks.Hob rock breaking simulation suggested that 5-10 s laser irradiation is optimal.