## 1 Introduction  
Microfractures sprout inside the natural rock mass, and the expansion and penetration of microfractures have a significant deteriorating effect on the bearing capacity [1; 2; 3; 4; 5]. This impact is especially more pronounced in rocks containing a high volume of water, as the long-term subsurface seepage accelerates the expansion of microfractures and reduces the overall stability [6; 7; 8; 9; 10]. Seepage reduces the effective stress between structural faces, which increases the slip shear damage of the fractured rock body along the dominant structural face [11; 12]. It is worth mentioning that the coupling of seepage and stress fields results in the propagation of microfractures, which affects the characteristics of the rock body [13; 14; 15; 16; 17]. Accordingly, the investigation of the water-rock coupling and the influencing mechanisms on the rock mass properties in the field of hydraulic engineering and tunnel construction is of significant importance. Numerous scholars have paid much attention to the hydro-rock mechanical characteristics of rock masses. [PERSON] et al. [18] explored the relationship between the fracture mechanical properties of granite and sandstone under hydro-rock action as well as the mode of immersion and the rate of solution flow. [PERSON], et al. [19] analyzed the damage fracture mechanical properties of fractured rock bodies under osmotic pressure. [PERSON], et al. [20] studied the interaction mechanism between seepage and damage deformation in fractured rock masses and established a coupled field-based seepage damage model for fractured rock masses. [PERSON], et al. [21] established a quantitative relationship between rock sound velocity and damage parameters for the whole process of uniaxial compression from the damage perspective. The study discussed the relationship between rock homogeneity and variation characteristics of sound velocity from the perspective of rock damage and deduced a conclusion that the Kaiser point was located near the point where the speed of sound begins to decline. [PERSON], et al. [22] studied the relationship between mechanical parameters of coal rock and water content, and established a segmental damage intrinsic model considering water content based on a uniaxial compression cycle test. The theoretical model can be used to analyze the uniaxial compressive stress-strain problem of coal rock under different water contents. Recently, the digital image correlation (DIC) method, acoustic emission (AE), and infrared radiation temperature (IRT) imaging have been widely employed for analyzing the damage evolution in rock masses. To explore the aging deformation and mechanical characteristics of damaged layered hard sandstone, [PERSON], et al. [10] used the digital image correlation technique and acoustic emission to obtain the displacement and strain fields and AE signals. The influence factor was introduced to establish a segmental statistical damage model, and the performed analyses revealed the model's accuracy under uniaxial compression. [PERSON], et al. [2] investigated the impact of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. [PERSON], et al. [23] carried out a uniaxial loading experiment on sandstone and collected AE signals synchronously. [PERSON], et al. [24] explored the characteristics of interlayer rocks using the thermal-mechanical coupling method. [PERSON], et al. [25; 26; 27] explored the acoustic emission properties and fracture properties ofuffs under the action of water-force coupling and established a fatigue intrinsic model of tuffs under the action of osmotic pressure. [PERSON], et al. [28] explored the diffusion-hydraulic properties of grouting geological rough fractures with power-law slurry. [PERSON], et al. [29] studied the hydro-mechanical behavior of the excavation-induced damage zone of Callovo-Oxfordian claystone. [PERSON], et al. [30] explored the influence of freeze-thaw cycles on the mechanical properties of pervious concrete.