## 1 Introduction  
The geomechanical behavior of rocks under freeze-thaw (F-T) action has drawn considerable attention due to its crucial role in many rock projects in cold regions [1; 2]. Since the implementation of the national strategy of \"One Belt, One Road\", many infrastructure projects such as highways, railroads, and open-pit mines [3] have been built in western China. However, the fact that western China belongs to a seasonal cold region with large temperature fluctuations in winter makes the outcropping rocks prone to F-T damage, so there are difficulties in maintaining rock projects in this region [4]. On the other hand, F-T damage changes the rock fracture process, which in turn affects the durability of the rock [5]. Therefore, exploring the effect of F-T damage on rock mechanical behavior and fracture processes has potential applications for engineering maintenance and safety assessment in cold regions. Extensive research efforts have been devoted to studying the changes in the physical and mechanical properties of rocks that are exposed to F-T action in cold regions [6; 7; 8; 9]. [PERSON] et al. [10] carried out a series of uniaxial tests on the rock that was subjected to F-T action and found that the uniaxial compressive strength and cohesion decreased significantly. They concluded that the F-T damage was irreversible due to plastic freeze-swell deformation, which occurs below 0 \({}^{\circ}\)C. [PERSON] et al. [11] investigated the effect of F-T cycles on the pore structure of red sandstone using high-pressure mercury injection tests and concluded that macropores in the samples are more sensitive to freeze-thaw action and may affect the fracture mode of the samples. In addition, based on the test results, [PERSON] et al. [12] found that the dynamic strength and modulus of the sandstone decreased exponentially due to the F-T action. [PERSON] et al. [13] studied the influence of pore structure evolution on the dynamic mechanical behavior of rocks using nuclear magnetic resonance and found that the evolution of pore structure leads to a decrease in the mechanical properties of rocks. The above studies have shown that the F-T effect influences the microstructure of rock, thus changing its mechanical response. In fact, rock failure is the result of the initiation and development of cracks under load until macroscopic cracks appear [14; 15]. Therefore, it is important to study the effects of F-T action on the stress threshold for the development of cracks in rock. However, these studies have focused more on the changes in the macroscopic mechanical properties of rock under F-T action than on the fracture behavior, and particularly few studies have focused on rocks in the Xinjiang region. Indeed, the application of acoustic emission technique (AE) is a reliable method to study the fracture behavior of rocks under load in the laboratory. In short, AE signals are the manifestation of microstructural behavior within the material and its intrinsic features, because intense AE behavior can reflect the fracture processes of rocks, including crushing of grains, the breakdown of pore structure, and the formation of micro-cracks [16]. Thus, several studies have explored the correlation between the F-T action and the AE signals of rocks. [PERSON] et al. [17; 18] studied the effects of cyclic F-T action on the mechanical and AE behavior of granite, and reported that F-T affected the frequency-domain characteristics of the AE signals and the signals in the sample became gradually active with the increase of F-T cycles. [PERSON] et al. [19] investigated the mechanical properties and failure processes of sandstone during thawing using the AE method and developed a damage model for frozen sandstone. [PERSON] et al. [20] pointed out that the critical exponent of AE probability density initially increased for each F-T cycle and then decreased with increasing cycle number by studying the damaged mechanical properties of rocks.