Progressive failure characteristics of coal under uniaxial compression: A comprehensive application of micro-ct and digital volume correlation

This study examines the failure process of coal under uniaxial compression using in-situ CT scanning with X-ray computed tomography. By integrating digital core technology and digital volume correlation (DVC), the research analyzes the development and evolution of fractures and calculates displacement and strain fields, offering reliable data for understanding failure mechanisms. Additionally, the study simulates fluid seepage within coal under varying loads, revealing the relationship between structural changes and permeability. The findings show that coal under uniaxial loading experiences both fracture development and compression, influenced by axial forces and the development of adjacent fractures. Minerals within coal play a guiding role in fracture development, shaped by their form and distribution. DVC results demonstrate that coal destruction is a dynamic, evolving process driven by deformation differences across regions and directions. Displacement vectors show coal matrix migration in multiple directions, while strain fields reveal lateral fracture expansion under axial compression. As loading progresses, fracture tortuosity decreases, and throat numbers rise to 6353, leading to increased permeability, notably a 149.35 μm² increase at the 1.1kN stage. This study deepens the understanding of coal's destructive characteristics and contributes to mining disaster prevention and control, with significant implications for coal engineering and resource development.