Determination of rock damage characteristics after laser irradiation based on computed tomography scanning and the nuclear magnetic resonance technique

Abstract

Efficiently crushing deep hard rock remains a significant engineering challenge. As an innovative rock-breaking technique, laser technology shows considerable promise for applications in deep engineering. Analyzing the damage characteristics of rock after laser irradiation and clarifying the mechanism of laser rock-breaking are crucial for advancing this technology towards practical engineering applications. Taking basalt as a typical representative of deep hard rock, we introduced computed tomography (CT) scanning and nuclear magnetic resonance (NMR) technology to study the internal macro and micro pore characteristics of the rock after laser irradiation with different power. Additionally, we reconstructed the morphology of the laser-drilled holes. The results show that the surface temperature of the rock under laser irradiation generally follows a Gauss?ian distribution, and the penetration depth of the 1250 W laser can reach 41.51 mm after 30 seconds. Laser irradiation affects the microscopic pores of the rock, causing small pores to expand into larger ones as the laser power increases. After laser irradiation, the molten holes can be categorized into drum-shaped and V-shaped zones, and the timely discharge of molten material enhances the efficiency of laser rock-breaking. These findings provide theoretical and technical support for the application of laser rock-breaking technology in the efficient crushing of deep hard rock and resource extraction.