## 1 Introduction  
In the process of deeply buried tunnel construction, deeply buried tunnels often experience high ground temperatures, and at the same time, due to the influence of blasting,boring or other construction factors, the surrounding rock strain rate will have a greater impact on the damage characteristics of the rock body [1]. Additionally, under high temperatures and different strain rates, granite is more prone to engineering hazards such as slab cracking and rock bursting. However, the current research on the effects of high temperature and strain rate on the mechanical properties and damage evolution of granite is insufficient. Therefore, an in-depth study of the damage evolution process of high-temperature granite under different loading rates is highly important for the design and construction of deeply buried tunnels. The mechanical characteristics of rocks exhibit notable variations when subjected to different loading rates and temperatures. In their study, [PERSON] et al. [2] explored the mechanical behavior of granite in the Three Gorges area. They found that the mechanical properties of granite initially increase, followed by a subsequent decrease as the temperature increases. [PERSON] et al. [3] conducted experiments on granite under various loading rates and temperature conditions. Their findings delineated the changes in rock mechanical properties at high temperatures and loading rates, considering the influence of temperature stages and fitting curves. [PERSON] et al. [4] conducted high-temperature triaxial compression tests on granite. They reported that the elastic modulus of granite decreased, then increased, then decreased with increasing temperature. In a high-temperature granite test, [PERSON] et al. [5] reported that the peak strength of granite increases suddenly at 300 \({}^{\circ}\)C. Consequently, the mechanical attributes of rocks experience significant alterations under the combined influence of temperature and loading rate, exhibiting an irregular developmental trajectory. In their investigation of the damage behavior of high-temperature rocks subjected to various loading rates, [PERSON] et al. [6] performed high-temperature triaxial compression tests on granite. They concluded that granite exhibits maximum brittleness and fragmentation at 300 \({}^{\circ}\)C. Additionally, [PERSON] et al. [7] noted a transition in the damage pattern of sandstone from mixed tensile-shear damage to oblique-shear damage with increasing temperature and loading rate. Furthermore, [PERSON] et al. [8] observed a pronounced trend of hard and brittle damage in rocks at higher temperatures within the range of 100 \({}^{\circ}\)C. These findings underscore the substantial changes in the mechanical properties and damage patterns of rocks under varying temperatures and loading rates. Moreover, existing research predominantly focuses on the damage and deterioration of rocks at elevated temperatures (above 100 \({}^{\circ}\)C), whereas investigations into the development of internal cracks and eventual failure of granite within the range of 100 \({}^{\circ}\)C remain relatively limited. The process of rock damage inherently involves the generation and dissipation of energy. Acoustic emission technology serves as a real-time monitoring tool capable of sensitively tracking the generation and outcomes of microfractures within rock samples [9]. Throughout the rock damage process, parameters, such as the acoustic emission ringing energy, b-value, and RA/AF can be employed to investigate the propagation and evolution of cracks within the rock, while acoustic emission localization points offer specific insights into crack distribution. In the realm of acoustic emission parameter analysis, [PERSON] et al. [10] discovered that the acoustic emission b-value and RA/AF can predict the rock damage point and its associated form. Moreover, [PERSON] et al.