## 4 Analysis of Test Results
### Analysis of Triaxial Compression Test Results  
#### 4.3.1 Deformation Properties  
The complete stress-strain curve of the triaxial compression test of the B group samples after the high temperature action is shown in Figure 12. It can be seen from Figure 12 that the regular triaxial compression stress-strain curve of the sample after the high temperature action is basically the same as that of Figure 7, and is roughly divided into four stages: compaction, elasticity, yielding, and failure. The deformation characteristics of the specimens are different under the action of temperature and confining pressure, and the axial compression deformation increases with the increase of temperature.  
Figure 11: Uniaxial compression failure modes after high temperature.  
example, in Figure 12e, after the 1000 \({}^{\circ}\)C high temperature effect, the densification of the B25 specimen is still obvious under the action of confining pressure of 25 MPa, and the initial nonlinear deformation is mainly dominated by crack closure. The elastic phase is mainly the elastic deformation of the mineral particles. The yield phase is mainly composed of inter-particle slip, elastic deformation, and yield deformation. The destruction phase is mainly macroscopic fissure slip and friction. Of course, the strength of the cement will decrease and the inter-particle slip will increase when specimen passes through a higher temperature.  
Under the same confining pressure, the relation between deformation parameters and temperature after different high temperature are shown in Figure 13. Compared with the results of the normal 25 \({}^{\circ}\)C test, the effect of high temperature within 400 \({}^{\circ}\)C has little effect on the deformation parameters. Once the temperature exceeds 400 \({}^{\circ}\)C, the impact on the elastic modulus, deformation modulus, and peak strain is greater. Although the sample is affected by its own heterogeneity, the test results are some discrete, and the high temperature still has some regularity effect on the specimen deformation parameters: the elastic modulus and the deformation modulus decreased monotonically with increasing temperature, and peak strain increased monotonically with increasing temperature. Compared with the normal 25 \({}^{\circ}\)C test results, after 600 \({}^{\circ}\)C, 800 \({}^{\circ}\)C and 1000 \({}^{\circ}\)C high temperature, the increase of elastic modulus by an average of \(-8.26\%\), \(-15.30\%\) and \(-33.30\%\), respectively; the decrease of deformation modulus by an average of \(-18.60\%\), \(-28.29\%\) and \(-47.33\%\), respectively; and the increase of axial strain in perk strength by an average of 48.41%, 79.57% and 113.21%, respectively.  
Figure 13: Relationship between temperature and deformation parameters of triaxial compression test.  
The above analysis shows that the high temperature effect within 400 \({}^{\circ}\)C has little effect on the deformation parameters of group B samples. Once the temperature exceeds 400 \({}^{\circ}\)C, the elastic modulus, deformation modulus and confining pressure of the sample are linearly positively correlated with temperature. There is a linear negative correlation and the peak strain is positively correlated with the confining pressure and temperature.