关键词: 单轴压缩, 声学特性, 破坏演化, 损伤变量

Abstract: In order to reveal the internal relationship between coal acoustic characteristic parameters and damage and failure evolution characteristics, the indoor test of coal acoustic monitoring under uniaxial compression is carried out, the variation law of coal wave velocity with strain is obtained, the evolution process of coal surface failure characteristics at different stages is analyzed, and the damage and failure degree of coal is quantitatively characterized by wave velocity, The correlation characteristics between wave velocity and mechanical characteristic parameters of coal at failure precursor point are discussed. The results show that with the increase of axial strain of coal body, the wave velocity shows a trend of stable, slow decrease and then sharp decrease. The surface morphology of coal sample has experienced the change process of no obvious change, small-scale macro failure and complete failure. The damage variable of coal body also shows the change law of almost zero, slow increase and then sharp increase. When the strain level reaches 95.55% and the stress level reaches 95.68%, the wave velocity level of coal body is 96.32%. The coal crack expands rapidly and instability disaster is about to occur.