基于应变能密度的非均质岩石损伤本构模型研究

Adopting the assumption that the elastic modulus of the rock mesoscopic unit approximately conforms to the Weibull distribution, a rock damage constitutive model was established based on the strain energy density theory. A method for determining the rock homogeneous degree coefficient m and the reduction factor of the elastic modulus K₀ was proposed using the AE(acoustic emission) energy signal and the rock longitudinal wave velocity, and the parameters were corrected as well. The uniaxial loading simulation was carried out by using the established damage constitutive model, and the simulation results were compared with the existing theoretical model and the uniaxial loading experimental results. It is shown that the proposed model can well describe the stress-strain relationship and acoustic emission conditions of specimens. The model was further used to simulate the repeated loading of plaster specimens and then to analyze stress, strain and acoustic emission characteristics, and comparison with the laboratory results was conducted. The research shows that the higher the homogeneous degree of the specimen is, the more obvious the characteristics of the brittle failure, and that the calculated results of m and K₀, which are determined based on the AE signal and the rock longitudinal wave velocity, agree with the experimental results. The established model provides a new theoretical basis for comprehensively considering the effects of rock homogeneous degree and repeated loading on rock specimens.