Viscoelastic-plastic damage creep model for salt rock based on fractional derivative theory

Wu, Fei; Zhang, Hao; Zou, Quanle; Li, Cunbao; Chen, Jie; Gao, Rutai

doi:10.1016/j.mechmat.2020.103600

Cited by 125 publications

(52 citation statements)

References 26 publications

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“…Defects of different scales such as pores, joints, cracks and dislocations are naturally formed in rocks in the long geological history process and uneven initial damages exist in rocks [ 20 , 21 ], but the development of initial damage has a stress threshold. Under the continuous action of the stress level above this threshold, the uneven and localized damage evolution phenomenon occurs, thus resulting in aging deformation and failure [ 22 ].…”

Section: Comparative Analysis Of Full Stress-strain Curve and Creep Curve Of Uniaxial Compression Testsmentioning

confidence: 99%

A novel nonlinear creep model based on damage characteristics of mudstone strength parameters

Cui

et al. 2021

PLoS ONE

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Mudstone interlayer is a weak layer in rock engineering. When it is subjected to continuous stress higher than its damage threshold, due to the dislocation of particles in mudstone crystals and the expansion of cracks, mudstone strength is gradually damaged and deteriorated and the strain gradually increases, thus accelerating the phenomenon of creep damage. In order to describe the characteristics of the whole process of mudstone aging deformation, based on the damage evolution of strength parameters (cohesion and internal friction coefficient) with stress and time in mudstone creep tests, a novel damage nonlinear viscoelastoplastic body (D-NVPB) is proposed through improving traditional plastic element. D-NVPB describes the nonlinear characteristics of the accelerated creep stage of mudstone. With the element combination method, D-NVPB is connected with the Burgers model in series to form a new nonlinear damage creep model (D-NVEP model). The analysis results of creep characteristics theoretically verified the rationality of the model in describing the instantaneous elasticity, viscoelasticity, and nonlinear viscoplastic characteristics of the complete creep curve of mudstone. With the data obtained in the uniaxial compression creep test of mudstone under the action of a stress level of 14 MPa, based on the Levenberg-Marquardt nonlinear least squares method, the fitting calculation was performed through piecewise fitting and overall fitting. The correlation coefficient was 0.9909, which verified the applicability of the model. The obtained model parameters by the identification were used to predict the mudstone creep curve under the stress levels of 13 MPa and 15 MPa. The good prediction results further verified the feasibility of the model. Compared with the traditional creep model, the D-NVEP model can better describe the nonlinear characteristics of the accelerated creep stage and quantitatively display the strength damage evolution process of rock in the creep failure process.

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Section: Comparative Analysis Of Full Stress-strain Curve and Creep Curve Of Uniaxial Compression Testsmentioning

confidence: 99%

A novel nonlinear creep model based on damage characteristics of mudstone strength parameters

Cui

et al. 2021

PLoS ONE

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“…Water is one of the unavoidable occurrence conditions of rock mass engineering [3]. With the rapid development of rock mass engineering such as slopes [4,5], tunnels [6,7], and underground caverns [8][9][10][11], water-rock interaction is highly valued. Rocks often contain microscopic defects such as pores and fissures, which become channels for water to enter the rock, thereby deteriorating its mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Research on the Influence of Moisture Condition on the Mechanical Properties and Microstructure of Sandstone

Luo

Zhu

Bai

et al. 2021

Shock and Vibration

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The sandstone from the dry to saturated state shows obvious deterioration characteristics. Taking the sandstone of a slope in the Three Gorges Reservoir area as the research object, uniaxial/triaxial compression of sandstone samples with different water-bearing states (dry, natural, and saturated) is carried out to study the changes in macromechanical properties of sandstone under different water-bearing states. Combined with NMR and SEM, the characteristics of microstructure of sandstone under different moisture conditions were studied. The results show that, with the increase of water content, the macromechanical parameters of sandstone gradually decrease, and the fine and microstructure characteristics are characterized by the gradual increase in the number of pores and the gradual increase in pore size. Based on the PFC2D software, considering the weakening effect of water on the partial cementation from a mesoscopic point of view, it is proposed to use soft and hard contacts to simulate the changes in the degree of cementation between particles under different water-bearing conditions and to study the impact of sandstone micromechanical parameters with changes in water content. Related research results can provide theoretical guidance for the stability evaluation of wading rock mass engineering.

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“…Xie et al [32] explored the distribution law of the abutment pressure in a coal seam, analyzed the mining dynamic characteristics of the peak value and position of the abutment pressure in front of the working face under the influence of mining, obtained the dynamic stress conditions due to mining of the coal body in front of the working face, and further carried out experimental research on the dynamic behavior of rock during coal mining. Wu et al [33,34] described the entire creep process of salt rock under triaxial loading, especially the creep characteristics in the accelerated creep stage, by replacing the Newtonian dashpot in the Maxwell model with the variable-order fractional derivative component and extending it from one to three dimensions. Zhang et al [35] further established an anisotropic coal permeability model considering the mining stress, fracture evolution, and gas adsorption-desorption effect.…”

Section: Introductionmentioning

confidence: 99%

The Ultrasonic P‐Wave Velocity‐Stress Relationship and Energy Evolution of Sandstone under Uniaxial Loading‐Unloading Conditions

Zhang

et al. 2021

Advances in Materials Science and Engineering

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As shallow resources are exhausted, deep resources are gradually being exploited; consequently, mining disasters and accidents have increased significantly over time. During mining, a deep rock mass experiences complex mining-induced stress evolution, damage accumulation, and deformation failure processes, and the mechanical and acoustic properties of the rock constantly change. To better understand the variation in the mechanical and acoustic properties of rock under loading and unloading conditions, uniaxial loading-unloading experiments with real-time ultrasonic P-wave velocity monitoring were conducted on sandstone specimens drilled from a coal seam roof. The test results show that the axial stress level is directly related to the P-wave velocity. A logarithmic relationship exists between the ultrasonic P-wave velocity and stress in the tested sandstones. The wave velocity increase caused by the unit axial pressure increase is significantly lower than that at the initial loading stage after entering the higher stress level. The energy evolution of sandstone during loading and unloading is closely related to the stress loading history and reflects the damage accumulation in the rock. Under elastic loading, the energy accumulation is mainly reflected by an increase in elastic energy, and less energy is dissipated during the elastic loading period. Stress unloading causes high energy dissipation, resulting in irreversible strain and damage accumulation, which provides a good basis for using ultrasonic testing to preliminarily judge the failure of a specific rock and formulate corresponding engineering measures.

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Viscoelastic-plastic damage creep model for salt rock based on fractional derivative theory

Cited by 125 publications

References 26 publications

A novel nonlinear creep model based on damage characteristics of mudstone strength parameters

A novel nonlinear creep model based on damage characteristics of mudstone strength parameters

Research on the Influence of Moisture Condition on the Mechanical Properties and Microstructure of Sandstone

The Ultrasonic P‐Wave Velocity‐Stress Relationship and Energy Evolution of Sandstone under Uniaxial Loading‐Unloading Conditions

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