Statistical damage simulation method for complete stress-strain path of rocks considering confining pressure effect and strength brittle drop

To establish a statistical damage simulation method which can accurately describe the full stress-strain curve of rocks, aiming at the serious defects of the existing statistical damage constitutive models in simulating confining pressure effect and strength brittle drop, firstly, based on the basic deformation characteristics of brittle rocks under triaxial compression, the rocks are regarded as a series of two meso-materials: soft and hard materials, and the deformation analysis model for macro-and meso-materials is established. Then, based on the instantaneous strain analysis method and statistical damage theory, the deformation analysis methods for the soft and hard materials are proposed respectively, so as to establish the statistical damage constitutive model for the full stress-strain curve of rocks considering confining pressure effect and strength brittle drop, and the determination methods for the model parameters are given. Finally, through model verification and analysis, the proposed model can describe the relationship between the initial macro-deformation characteristics of rocks and the confining pressure and eliminate the randomness of the axial post-peak theoretical deformation curve, so it can accurately simulate the full stress-strain curve of rocks, which shows that the above methods are reasonable and feasible.