Permeability Evolution Laws and Equations during the Course of Deformation and Failure of Brittle Rock

Deep brittle rock exhibits characteristics of rapid stress dropping rate and large stress dropping degree after peak failure. To simulate the whole process of deformation and failure of the deep brittle rock under load, the Lemaitre strain equivalent theory is modified to make the damaged part of the rock has residual stress. Based on the damage constitutive model considering residual strength characteristics, a correction factor reflecting stress dropping rate is added, the Weibull distribution is used to describe the inhomogeneity of rock materials, and Drucker–Prager criterion is used to quantitatively describe the influence of stress on damage; a damage constitutive model of deep brittle rock considering stress dropping characteristics is established. According to the geometric features of the rock stress-strain curve, the theoretical expressions of model parameters are derived. To verify the rationality of the model, triaxial compression experiments of deep brittle rock under different confining pressures are conducted. And the influence of model parameters on rock mechanical behaviour is analysed. The results show that the model reflects the stress dropping characteristics of deep brittle rock and the theoretical curve is in good agreement with the experimental results, which indicates that the proposed constitutive model is scientific and feasible.

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Experimental Study on the Relationship between Compression Stability and Deformation Localization of Viscous/Brittle Rock-Like Materials

Advances in Materials Science and Engineering ◽

10.1155/2021/7153661 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Xiangfeng Lv ◽

Yahan Yang ◽

Yan Chen ◽

Nianjin Wang ◽

Min Yang ◽

...

Keyword(s):

Physical Map ◽

Quantitative Description ◽

Test Method ◽

Brittle Rock ◽

Deformation Localization ◽

Deformation And Failure ◽

Deformation Stage ◽

Compression Deformation ◽

Localization Zone ◽

Monitoring Test

Rock-like materials often exhibit irregular failure deformation under long-term service conditions, and the deformation and failure of asphalt and concrete materials is a serious problem that leads to subgrade failure. In this study, two different viscous/brittle rock-like materials were prepared by the in situ loading and optical speckle synchronous monitoring test method, and the evolution characteristics of the deformation field were studied during compression. The formation process of the compression deformation localization of rock-like materials and their relationship with stability were analyzed. A quantitative description of the compression deformation stage and localization characteristics of the viscous/brittle rock-like materials is presented. The results can be summarized as follows. At the initial stage of compression, the deformation localization zone of viscous/brittle rock-like materials begins to expand from the middle area to the surrounding area. Preliminary results of the deformation localization of the linear elastic deformation stage were obtained. The failure cloud image is completely formed at the peak, which is consistent with the failure physical map. The deformation process of compression can be quantitatively described using the deformation localization characteristics of rock-like materials.

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