By studying the mechanical characteristics of sandstone, particularly its acoustic emission (AE) behaviour and fracture morphology, we can obtain insights into its deformation, stress, and fracture mechanisms, thus promoting knowledge in the field of geology. In this work, the mechanical properties of sandstone samples with different joint angles were investigated by applying shear force and observing the fracture propagation trend on a microscopic scale, using an AE-based technique. The experimental results demonstrated that the fracture expansion trend altered from a shearing fracture, which developed from the top to the lower areas of the samples, to a tensile fracture in the middle area of the samples and escalated in the angled joints; in particular, the severity of the fracture maximised at a joint angle of 60°. The energy released during the crack formation can be indicated by the decibels produced from the AE signal. While investigating the AE signals of the samples during shearing, it was determined that the decibels obeyed a Gaussian distribution centred at 50–69 dB. The surface fractures were macroscopically analysed through the self-defined fracture dispersion and fractal dimension, revealing that as the joint angle increased, the fracture dispersion initially increased and subsequently decreased, reaching its maximum at 60°, whereas the fractal dimension constantly increased. Through our investigation on the mechanical properties, main failure modes, AE characteristics, and microscopic features of sandstone, we aimed to elucidate the mechanisms responsible for fracture propagation both on a macroscopic and microscopic scale and provide theoretical insight in the field of geological disaster.

通过研究砂岩的力学特性，特别是其声发射 (AE) 行为和断裂形态，我们可以深入了解其变形、应力和断裂机制，从而促进地质领域的知识。在这项工作中，使用基于 AE 的技术，通过施加剪切力并在微观尺度上观察裂缝扩展趋势，研究了具有不同节理角度的砂岩样品的力学性能。实验结果表明，断裂扩展趋势由从试样顶部向下部发展的剪切断裂转变为试样中部的拉伸断裂，并在斜接缝处升级；特别是，骨折的严重程度在关节角度为 60° 时达到最大。裂纹形成过程中释放的能量可以通过 AE 信号产生的分贝来表示。在研究剪切过程中样品的 AE 信号时，确定分贝服从以 50-69 dB 为中心的高斯分布。通过自定义裂缝弥散度和分形维数对地表裂缝进行宏观分析，发现随着节理角度的增加，裂缝弥散度先增加后减小，在60°处达到最大值，而分形维数不断增加。通过对砂岩力学性能、主要破坏模式、声发射特征和微观特征的研究，