Acta Geodynamica et Geomaterialia

Title: DIFFERENCES IN STRENGTH, SEEPAGE, AND ACOUSTIC EMISSION CHARACTERISTICS OF RAW COAL AND BRIQUETTE COAL SAMPLES: A TRIAXIAL COMPRESSION EXPERIMENT INVESTIGATION
Authors: Zhou Baokun, Zhang Erhui, Dong Xukai, Li Changfeng and Li Ping
DOI: 10.13168/AGG.2024.0009
Journal: Acta Geodynamica et Geomaterialia, Vol. 21, No. 1 (213), Prague 2024
Full Text: PDF file (5.7 MB)
Keywords: Raw coal and briquettes coal; Triaxial experiment; Strength characteristics; Acoustic emission; Seepage; Stress sensitivity; Seepage Sensitivity
Abstract: The differences in intensity, acoustic emission (AE), and seepage characteristics between raw coal and briquette coal were studied under a triaxial compression experiment. The two stress-strain curves of raw coal and briquette coal had similar trends and could be divided into five development stages in the triaxial compression experiment. The transverse and axial deformations of briquette coal were larger than those of raw coal, and the compressive strength and elastic modulus of briquette coal were smaller than those of raw coal. The cumulative AE count and energy of the whole compression process of raw coal were higher than that of briquette coal. The seepage velocities of gases increased with the deformation and failure of coal samples, and its variation trend corresponded to the failure stage of coal samples. Their permeability velocity was small at the initial stage of raw coal and briquette coal. However, the maximum permeability velocity of briquette coal was much higher than that of raw coal after the failure of coal samples. Both raw coal and briquette coal had strong stress sensitivity. The permeability of the two types of samples decreased exponentially with the increased effective stress. The seepage velocity of briquette coal was most sensitive to axial force and deformation, while that of raw coal was more sensitive to radial deformation. The research results provide references for the experimental study of using briquette coal instead of raw coal as well as for exploring coal and gas outburst mechanisms in coal seam.