Fracture damage and energy evolution of fissured coal subject to triaxial unloading condition

• DOI: 10.1007/s40789-025-00778-1
• Publication Date: 2025-04-07T16:58:56Z
• Authors: Zhijie Zhu; Peng Wang; Xiaohan Yang; Jan Nemcik; Ting Ren; Laigui Wang; Jun Han; Songsong Guan

Abstract Fissured coal mass under triaxial unloading condition exhibits higher burst potential than the loading condition, which poses challenge to safety and productivity of resources extraction underground space utilization. To comprehensively understand mechanism unloading-induced during excavation process, this study investigated fracture energy evolution samples with different fissure types such as single, two parallel, coplanar-parallel using PFC 2D modelling. Triaxial tests were conducted determine compressive strengths other parameters. With increase inclination angle, strength decreases for β = 0°–30°, then 30°–90°. The fissures is highest. Fissure can significantly change distribution elastic energy. Secondary cracks generated starting from both ends fissure. For 0°–60°, low strain area was produced around along direction. transferred outside fissures. 75°–90°, only a small amount high on sides expansion conditions occurred due tensile stress T caused by differential rebound deformation shear surface.