According to the damage mechanism of rock materials

a set of constitutive equations with temperature effect taken into account has been obtained by means of introducing two damage variables into endochronic theory. The constitutive equations can be used to describe the rock material deformation process at different temperatures and under different loadings. The damage variables represent respectively hydrostatic stress decrease in void rate and fracture due to deviatoric stresses. The parameters in the constitutive equations can be determined by uniaxial stress-strain curves. Experiments on marble samples have been performed in the temperature range of 20℃-500℃ at an interval of 50℃ and all material parameters in constitutive equations were determined by experimental results.