Statistical damage simulation method of strain softening deformation process for rocks considering characteristics of void compaction stage

To establish a good simulation method for the full deformation and failure process of rocks, the deficiencies and limitations of the existing statistical damage constitutive models for rocks are investigated, which can not reflect the nonlinear deformation characteristics at the initial void compaction stage. Firstly, based on the full discussion of the deformation mechanism of porous rocks and the combination of the methods for macro analysis and micro analysis, a deformation analysis model for porous rocks is established by abstracting porous rocks into two parts, rock skeletons and voids. Then, on the basis of the discussion of the deformation mechanism of void part, a deformation analysis method for void part is proposed by considering the unrecoverable characteristics of deformation caused by void compaction. Meanwhile, a deformation analysis method for skeleton part is also developed by introducing the statistical damage theory. Moreover, a new statistical damage constitutive model to simulate the full deformation and failure process of porous rocks is hence established, and the relevant determination methods for the model parameters are also provided. This model can reflect the properties of strain softening deformation of porous rocks and the characteristics of the nonlinear deformation at the initial void compaction stage. Finally, the rationality and superiority of this model are validated by comparing the experimental and theoretical curves of the proposed model and other existing similar models.