## 3 Test Results
### Changes in Uniaxial Compressive Strength and Elastic Modulus  
Figure 10 illustrates the relationship between the uniaxial compressive strength of granite and temperature variation. As shown in the Figure 10, the uniaxial compressive strength of granite decreased with an increasing temperature, but the uniaxial compressive strength of granite sampled in the different directions shows different trends: At room temperature, the Z-direction granite had the highest strength, followed by the X-direction granite, and the Y-direction granite had the lowest strength. As the temperature increased from room temperature to 400 \({}^{\circ}\)C, the strength of the granite decreased. The difference in the uniaxial compressive strength of granite in the three directions rapidly decreased within this temperature range, and the strength of granite in the Z direction was slightly greater than that in the X and Y directions. When the temperature increased to 600 \({}^{\circ}\)C, the strength of granite in the three directions decreased rapidly, and the strength of granite in the Y direction was relatively lower than that in the other two directions. As the temperature continued to rise, after the high temperature increased to 800 \({}^{\circ}\)C and 1000 \({}^{\circ}\)C, the strength differences in the three directions gradually disappeared and tended to be consistent. Figure 10: Temperature-dependent variation in the uniaxial compressive strength of granite under different sampling directions. For samples obtained from different sampling directions, within the temperature range of room temperature to 600 \({}^{\circ}\)C, the changes in the strength of granite in the X and Y directions were relatively similar, both showing slight decreases in the uniaxial compressive strength after being subjected to temperatures below 400 \({}^{\circ}\)C. At 400 \({}^{\circ}\)C, the strength in the X and Y directions decreased by 12.62% and 13.32%, respectively, compared to that in the room-temperature state. As the temperature rose to 600 \({}^{\circ}\)C, the strength in the X and Y directions decreased by 31.89% and 33.57%, respectively, compared to that in the room-temperature state. However, the variation trend of granite sampled in the Z direction within this temperature range significantly differed. As the temperature increased, the uniaxial compressive strength of granite in the Z direction approximately decreased linearly, and the rate of decrease was much greater than that in the other two sampling directions. At 600 \({}^{\circ}\)C, the uniaxial compressive strength of granite in the Z direction decreased by 45.38% compared to that at room temperature. When the heating temperature was higher than 600 \({}^{\circ}\)C, the difference in the trend of the uniaxial compressive strength of granite in the three sampling directions gradually decreased, and the rate of strength reduction slowed down in the range of 600-800 \({}^{\circ}\)C. At 1000 \({}^{\circ}\)C, the strength of granite rapidly decayed to the minimum value, and the uniaxial compressive strength of granite in the X, Y, and Z directions decreased by 66.24%, 63.14%, and 75.08%, respectively, compared to that at room temperature. Figure 11 shows the relationship between the elastic modulus of granite and temperature variation. The elastic modulus of granite in the X direction was 25.74 GPa at room temperature, which slightly decreased before 400 \({}^{\circ}\)C and decreased to 23.14 GPa at 400 \({}^{\circ}\)C for a decrease of 10.15% compared to room temperature. When the temperature was above 400 \({}^{\circ}\)C, the elastic modulus decreased almost linearly and dropped to 4.75 GPa at 1000 \({}^{\circ}\)C, a decrease of 81.54% compared to room temperature. The elastic modulus of granite in the Y direction at room temperature was 23.30 GPa, which was slightly lower than that in the X direction. As the temperature increased, the rate of decrease in the elastic modulus gradually accelerated.