Analysis on damage mechanical characteristics of marble exposed to high temperature

Study on the mechanical response of rock under the combined effects of high temperature and mechanical load using the method of damage mechanics is a relatively new research direction of rock mechanics. The thermal damage and mechanical damage are indicated by the uniaxial compression mechanical test of marble after exposure to high temperature. The overall damage evolution equation of rock is deduced and high-temperature damage constitutive equation is established on the basis of the macroscopic phenomenological damage mechanics and nonequilibrium statistical methods. The evolution law of the damage characteristics of rock after exposure to high temperature, taking the temperature and mechanical load as the control variable, is discussed. The results show that the effect of temperature on the mechanical properties of marble can be accurately described through the definition of thermal damage using elastic modulus. The high-temperature damage constitutive model curves are similar to the experimental curves, reflecting well the brittleness of marble. Additionally, the constitutive relations of rock after exposure to high temperature have close relationships with the elastic modulus, compressive strength, and peak strain. The overall damage of rock changes along two evolutionary pathways of high temperature and strain, reflecting the mutual combined influences of high temperature and strain on the material damage extension, can accurately reveal the damage mechanical behavior and the damage propagation law of rock material after exposure to high temperature.