A quantitative model considering crack closure effect of rock materials. (1st September 2022) - Xie, Shijie
Highlights: A quantitative model is proposed to describe the influence of the crack closure effect on the constitutive relation. The proposed model can simulate the nonlinear phase of the stress–strain curve of rocks under uniaxial and triaxial compression conditions. The material damage caused by microcracks can be identified and quantified by the microcrack volume ratio. Abstract: The crack closure effect of rock materials plays a key role in the evaluation of its compressive mechanical behavior. Based on the effective medium theory, an exponential model is proposed to describe the influence of the crack closure effect on the constitutive relation. The crack deformation is characterized by natural strain, and the crack propagation in the compaction phase and elastic phase can be captured by this quantitative model. Three model parameters can be determined from experimental data. The model was verified by our uniaxial compression tests on marble and other types of rocks from the published literature. The results show that the model can simulate the nonlinear phase of stress–strain curves of rocks under uniaxial and triaxial compression conditions. The crack closure behavior in the compression tests can be well reflected by this model. In addition, the microcrack volume ratio is positively correlated with the crack density parameters, and the material damage caused by microcracks can be identified and quantified by the microcrack volume ratio.