Study on Mechanical Properties and Damage Evolution Law of Granite after High Temperature Cooling

In this paper, uniaxial compression test is performed on granites cooled at different temperatures to study mechanical characteristics of granites. Main conclusions are as follows: (1) the stress-strain curves of rocks after high temperature cooling show characteristics of brittle fracture, dividing into four stages: compaction stage, linear elastic stage, weakening stage and failure stage. (2) There are two temperature thresholds for the influence of temperature on the mechanical properties of rocks: mechanical properties of the rock deteriorate with increasing temperature between the room temperature and first temperature threshold; in the second temperature threshold range, The mechanical properties of the rock are gradually strengthened as the temperature rises; when the temperature exceeds the second temperature threshold, the mechanical properties of the rock gradually deteriorate. (3) Based on Weibull distribution, the damage evolution laws are proposed and the corresponding constitutive equations are derived. And the theoretical model can partially reflect the mechanical properties of the rock under different temperatures.