###### Abstract  
Transversely isotropic rocks, which are special anisotropic materials, are widely encountered in civil, mining, petroleum, geothermal, and radioactive waste-disposal engineering. Rock is frequently subject to cyclic loads resulting from natural and human-caused events. However, to date, the fracture mechanism of transversely isotropic rocks under cyclic loading remains poorly understood. To address this gap, uniaxial monotonic-loading and cyclic-loading tests were performed on slate specimens by the MTS815 system, during which acoustic emission (AE) signals inside the rock were monitored, and finally the fracture surfaces of the tested rock were scanned by scanning electron microscopy (SEM). Through these tests, the anisotropic mechanical properties, damage evolution, AE characteristics and fracture pattern of slate as a transversely isotropic rock were studied. The results show that the peak strength of specimens varies with the loading-foliation angle under monotonic and cyclic loading, following a U-shaped trend. The deformation modulus during unloading is more capable of characterizing the damage inside the specimen than that during loading. By defining the damage degree based on dissipation energy, it is found that the damage variable is influenced by the loading-foliation angle and the cyclic stress step. The AE characteristics of specimens exhibit significant anisotropy, closely correlated to the loading condition and loading-foliation angle. Regardless of cyclic stress step, the AE counts of specimens with a loading-foliation angle of 0\({}^{\circ}\) are mainly distributed near the peak region, whereas those of specimens with other loading-foliation angles occur primarily in the early stage of each cyclic loading. Finally, it is revealed that the fracture mechanism of slate specimens is determined by the loading-foliation angle, loading condition, and cyclic stress step. t 20242020244 June 20242024 June 20242024 June 20242024 June 202420244 June 202420244 June 202420244 June 202420244 June 202420244444444444444444444444444444444444444444444444444444444444  
To date, there have been numerous studies on the mechanical behavior of rocks under cyclic loading, which have explored the deformation, strength, energy evolution, acoustic emission signal, and fatigue damage characteristics of rocks under different cyclic-loading stress paths [12; 13; 14; 15; 16; 17; 18]. They have discovered some inherent characteristics of rocks under cyclic loading, such as residual strain, hysteresis loop, fatigue threshold, stress memory, the Kaiser effect, and the Felicity effect. For instance, [PERSON] et al. [19] investigated the relationship between size effect and cyclic response of cylindrical specimens. [PERSON] et al. [15; 20] investigated the effects of loading frequency and the lower limit of cyclic stress on the deformation characteristics of sandstone by triaxial cyclic-loading tests. They pointed out that increasing the cycle frequency inhibited the development of primary and new cracks in the rock during the compaction and plastic stages, while increasing the lower limit of cyclic stress shortened the time of volumetric compaction and produced the volumetric expansion of the specimen in advance. [PERSON] et al. [21] studied the effect of random cyclic loading on intermittent jointed rocks, and their results showed that both the fatigue strength and deformation modulus of specimens decreased with the increase in loading time, but increased with the increase in loading amplitude. [PERSON] and [PERSON] [22] investigated the deformation and dissipation energy of sandstone under uniaxial cyclic loading, and found that the energy-dissipation curve could reflect the fatigue deformation of sandstone. In addition, some scholars have carried out experimental studies on the post-peak behavior of rocks under cyclic loading [23; 24].