Triaxial Creep Behavior of Red Sandstone in Freeze-Thaw Environments

Song, Yongjun; Che, Yongxin; Zhang, Leitao; Ren, Jihong; Chen, Shaojie; Hu, Mengling

doi:10.1155/2020/6641377

Cited by 23 publications

(10 citation statements)

References 35 publications

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“…The author introduces the damage variable D to describe the creep damage degradation of the viscosity coefficient and constructs a viscoplastic body considering the damage. Its constitutive equation can be written as follows 29 : where τ is the shear stress of the damaged viscoplastic body, is the strain rate of the damaged viscoplastic body, and η 2 ( t ) is the function of the viscosity coefficient related to time.…”

Section: Establishment Of the Nonlinear Shear Creep Damage Modelmentioning

confidence: 99%

Shear creep mechanical properties and damage model of mudstone in open-pit coal mine

Wang

et al. 2022

Sci Rep

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Clarifying the shear creep characteristics of rock and scientifically analyzing its creep deformation law is the key to solving the problem of safe construction and long-term stability analysis of the open-pit coal slope rock mass. Shear creep tests were carried out on mudstone from an open-pit coal mine in Eastern Mongolia to reveal the creep characteristics of mudstone under different normal and shear stresses. Based on the classical Nishihara model, a new composite six-element nonlinear shear creep damage model is established by introducing nonlinear elastomers. Using the least square method, model verification and parameter identification are carried out on the variable test data. At the same time, the influence law of the model parameters on the rock creep deformation is analyzed according to the theoretical curve. The study results showed that the nonlinear shear creeps damage model could better describe the creep characteristics of rock different normal stress and shear stress levels, significantly the non-linear both the strain and time of attenuation creep and accelerated creep. The creep characteristics of the accelerated creep stage described by this model are better than those described by the classical Nishihara model. The model curve is consistent with the changing trend of the experimental data, and the degree of agreement is very high. The correlation coefficients are all above 0.98, which verifies the accuracy and rationality of the model. The influence law of creep parameters is analyzed. The parameters b and c increase nonlinearly with creep. The increase of λ accelerates the process of rock attenuation creep stage; the increase of η10 slows down the progress of rock decay creep stage; with the increase of α, the deformation and creep rate of rock in accelerated creep stage gradually increase. When η2 increases, the deformation in the acceleration stage decreases gradually. The research results can provide important theoretical support for the safe construction and long-term stability analysis of open-pit coal slope rock masses.

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Section: Establishment Of the Nonlinear Shear Creep Damage Modelmentioning

confidence: 99%

Shear creep mechanical properties and damage model of mudstone in open-pit coal mine

Wang

et al. 2022

Sci Rep

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“…In Formula (12), α and m are the physical and mechanical parameters of the material, where α is the Weibull distribution parameter and m represents the non-uniformity of the distribution. Formulas (11) and (12) can produce…”

Section: Theoretical Analysis Of Sandstone Damage Characteristics Aft...mentioning

confidence: 99%

“…The extent of red sandstone degradation was considered quantitatively using various mechanical parameters such as the ultimate stress, elastic modulus, and Poisson's ratio. Song et al [11] investigated the time-dependent mechanical properties of rock masses in cold regions under the effects of freeze-thaw cycling and long-term loading. Triaxial multilevel loading and unloading creep tests were performed on saturated red sandstone samples that were subjected to various numbers of freeze-thaw cycles.…”

Section: Introductionmentioning

confidence: 99%

Study on Acoustic Emission and Damage Mechanical Properties of Freeze-Thaw Sandstone under Uniaxial Compression

Liang

Yang

2022

Geofluids

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The damage strength of freeze-thaw rock provides an important reference for stability evaluations used during rock engineering in cold regions. In this paper, real-time acoustic emission tests of saturated sandstone are performed after various freeze-thaw cycles to study the uniaxial compressive strength and deformation characteristics of the resulting materials. The macro-meso damage evolution law of loaded sandstone is studied under the action of freeze-thaw cycles. The results show the following: (1) The saturated water absorption of sandstone increases, the peak strength and elastic modulus loss rates of sandstone increase linearly, and the frost resistance of the rock decreases with the number of freeze-thaw cycles. The sandstone failure mode gradually shifts from splitting failure to complex splitting shear failure of the failure surface. (2) If fewer than 10 freeze-thaw cycles are applied, the ring count signals at the compaction stage and after the peak strength is reached are extremely weak under a uniaxial compression load. With additional freeze-thaw cycles, damage inside the rock accumulates gradually, and the ring count signal appears during the rock compaction stage, fluctuates up and down, and continues until the peak strength is reached. When the compressive strength reaches its peak, the ring count intensity signal increases suddenly, and the frequency is high. After the strength reaches its peak, the acoustic emission signal shows that the rock sample still has some residual strength. As the number of freeze-thaw cycles increases, the cumulative ring count of sandstone gradually changes from the jumping stage to gradual growth. The acoustic emission characteristic parameters and ring count reflect damage to and expansion of freeze-thaw sandstone. (3) The cumulative extent of rock damage reaches the threshold value under loading and increases linearly until the rock is destroyed. When more freeze-thaw cycles are used, the time required for the rock to reach this threshold value is shorter, and the time required for sandstone damage is reduced gradually. These results provide a reference for the study of freeze-thaw damage and rock stability in cold regions.

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“…According to the results of the multistage loading creep tests, the axial creep curves of the coal specimens with different inclination angles at each creep loading levels were obtained by using the Boltzmann superposition principle [27][28][29]. These curves are shown in Figure 11.…”

Section: Influence Of Specimen Inclination On Time-dependentmentioning

confidence: 99%

Experimental Investigations on Creep Behavior of Coal under Combined Compression and Shear Loading

Hou

Zhang

et al. 2021

Geofluids

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The creep behavior of rock has received much attention for analyzing the long-term response and stability of underground rock engineering structures. Numerous studies have been carried out on the creep properties of various rocks under pure compression conditions. However, little attention has been paid to the creep behavior of rocks in a combined compression-shear loading state. In this work, a novel combined compression and shear test (C-CAST) system was used to carry out inclined uniaxial compression tests and creep tests for various inclination angles (0°, 5°, 10°, and 15°). The results revealed that the peak strength of the coal decreased with the inclination angle of the specimen, which could provide the basis for setting up a creep test scheme. Multistage compression-shear creep tests were carried out on specimens with different inclination angles. Based on the analysis of the creep test data, the creep behavior of the coal in a combined compression-shear state was studied. It was found that the specimen inclination affected the time-dependent deformation, long-term strength (LTS), and time to failure. Compared with the specimen under pure compression, the inclination specimens tend to produce large shear strain with time, while they were more prone to shear failure. The reduction of the long-term strength was closely associated with the increase of the specimen inclination angle when the angle was more than 5°. Moreover, the ratio of the peak strength to the LTS was not affected by the specimen inclination, which is considered an inherent characteristic. We anticipate that the results obtained will assist in pillar design and long-term stability analysis.

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Triaxial Creep Behavior of Red Sandstone in Freeze-Thaw Environments

Cited by 23 publications

References 35 publications

Shear creep mechanical properties and damage model of mudstone in open-pit coal mine

Shear creep mechanical properties and damage model of mudstone in open-pit coal mine

Study on Acoustic Emission and Damage Mechanical Properties of Freeze-Thaw Sandstone under Uniaxial Compression

Experimental Investigations on Creep Behavior of Coal under Combined Compression and Shear Loading

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