Experimental and numerical investigation of laser-induced rock damage and the implications for laser-assisted rock cutting

Abstract High-energy laser technology is expected to be applied into deep drilling and tunnel excavation due to its attractive prospects for enhanced hard rock breakage. However, there is still a lack of proper experimental methods and numerical tools to quantitatively evaluate the influence of laser radiation on rock fracture. Combined with our specially designed experimental tests, this work aims to provide a numerical tool to quantitatively investigate laser-induced rock damage. Using a specially designed experimental platform, we conducted direct tensile tests on rock samples in the shape of dog-bone to determine rock damage under the laser radiation of different parameters. The experimental results show that a high-energy laser beam can cause a significant loss in rock tensile strength. Then, a mathematical model was established to describe the temporal and spatial evolution of rock damage in a given path of laser scanning, which was implemented in a four-dimensional lattice spring model (4D-LSM) to simulate our experimental tests. Through a comparison between the numerical and experimental results, the multiparameter damage model was proven to be more suitable for the numerical simulation of laser-induced rock damage. Finally, by introducing a laser damage model, an orthogonal experimental design was used to analyse the influencing significance of different factors on the efficiency of rock breaking and the wear of cutter tools in laser-assisted rock cutting, showing the prospects for application of the proposed numerical model to laser-assisted tunnel boring machine (TBM) tunnelling in the future.