Micro-rupture and deformation analysis of different rocks using AE and DIC techniques

Surface deformation and internal micro-fracturing provide valuable insights into rock damage assessment. Establishing correlations between these phenomena is crucial for deciphering rock failure mechanisms. This study systematically examines three representative lithotypes—sandstone, metagabbro, and granite—through Brazilian splitting tests coupled with digital image correlation and acoustic emission monitoring. The results reveal lithotype-dependent damage characteristics governed by inter-particle sliding dynamics and particulate deformation mechanisms. Sandstone displayed pronounced strain localization during stress accumulation, whereas metagabbro demonstrated a superior peak failure energy compared to granite. Fracture mode analysis indicated tensile-dominated failure in sandstone and granite, in contrast to metagabbro’s hybrid failure mechanism. This divergence likely originated from differential inter-particle stress concentration patterns. Metagabbro’s damage pattern deviated from maximum principal strain correlations, a phenomenon potentially attributable to its unique internal particle size distribution. This study offers insights into tensile-induced fracture mechanics of deep rock formations.