Study of the Acoustic Characteristics and Evolution of the Failure Mode of Yellow Sandstone Under Uniaxial Compression

The acoustic characteristics of the rock failure process can reflect the evolution of crack development and expansion. To study the evolution of different types of internal cracks during the rock failure process, the acoustic emission (AE) signal of the yellow sandstone under uniaxial compression was collected with AE monitoring technology, and the acoustic characteristics, crack types and evolution of the correlation dimension of the rock failure process were studied. The parameter analysis of RA (rise time/amplitude) and AF (counts/duration) for classifying different cracking modes during loading revealed that tensile cracks are dominated in the crack closure stage and linear elastic deformation stage, and the proportion of shear cracks increased in the plastic deformation stage and the post-peak failure stage. High-energy events were more widely distributed in the areas of shear cracks. The average AE energy of shear cracks is higher than that of tensile cracks, and the AE energy ratio for shear cracks and tensile cracks is within the range of 4.29–4.78. The correlation between stress and AE data was calculated using fractal theory methods and Grassberger–Procaccia (G–P) algorithms to study the evolution of different types of internal cracks. The correlation dimension displayed a stable stage, a descending stage and a fluctuating low value stage. The descending stage and the fluctuating low value stage appeared during the plastic deformation stage and the post-peak failure stage, respectively, indicating that the type of rock internal micro-crack changed greatly in the above two stages. The findings in this study contribute to better understanding of the rock failure mechanism.