Verification of concrete nonlinear creep mechanism based on meso-damage mechanics

Yu, Li; Shen, Qiang; Xu, Wenqiang; Xia, Hua; Xu, Chao; Lai, Jiayu; Yuan, Min; Chen, Bo

doi:10.1016/j.conbuildmat.2020.122205

Cited by 23 publications

(12 citation statements)

References 20 publications

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“…CGBBs are viscoelastic plastic bodies, and the linear parallel bond model can well re ect the elastoplasticity of the cemented materials (Li et al 2021). Therefore, the lineal parallel bond model was adopted in this simulation.…”

Section: Numerical Simulation Analysismentioning

confidence: 99%

Failure properties and stability monitoring of strip and column cemented gangue backfill bodies under uniaxial compression in constructional backfill mining

Ran

Yao

Feng

et al. 2022

Environ Sci Pollut Res

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The strip and column cemented gangue back ll bodies (CGBBs) are the main supporting components in the design of constructional back ll mining for coal mining, which determines the stability of goaf. Previous researches have mostly focused on the mechanical properties of column CGBB, but the mechanical properties of strip CGBB are still unclear. Herein, the uniaxial compression experiments for strip and column CGBBs were conducted to compare the failure properties. The acoustic emission (AE) and two types of resistivity monitoring were used to monitor the damage evolution. The effect of the length-height ratio on the mechanical characteristic of strip CGBB was analyzed by discrete element simulation. The results show that: the strength and peak strain of strip CGBB under uniaxial compression is higher than those of column CGBB, and the strip CGBB shows better ductility. The stress of column CGBB decreases signi cantly faster than that of strip CGBB at the post-peak stage. The strength and ductility of strip CGBB increase with the increase of length-height ratio.The strip CGBB is destroyed from both ends to the middle under uniaxial compression, and the core bearing area is reduced correspondingly. The AE signal evolution of CGBBs under uniaxial compression before the peak stress contains three stages, and the AE signals of strip CGBB at the peak stress will not rise sharply compared with column CGBB. The resistivity monitoring effect of the horizontally symmetrical conductive mesh is better than that of the axial. The horizontal resistivity increases gradually with the increase of stress under uniaxial compression, and increases sharply at the peak stress, and then drops after the peak stress. The damage constitutive models and the stability monitoring models of the CGBBs are established based on the experimental results. This work would be instructive for the design and stability monitoring of CGBB.

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Section: Numerical Simulation Analysismentioning

confidence: 99%

Failure properties and stability monitoring of strip and column cemented gangue backfill bodies under uniaxial compression in constructional backfill mining

Ran

Yao

Feng

et al. 2022

Environ Sci Pollut Res

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“…In the later stage, with the viscous flow of the cement gel, the stress concentration gradually dissipated, and the creep rate showed a decreasing trend and finally remained stable. At the same time, with the continuous generation and expansion of micro-cracks, the microscopic damage continued to accumulate ( 9 ). In the attenuation creep stage, it is the nature of the viscous element that determines the greater the viscosity coefficient, the smaller the creep rate under the same stress level.…”

Section: Discussionmentioning

confidence: 99%

“…Since the beginning of the twentieth century, many scholars have done a lot of in-depth research on concrete creep. It is generally believed that the creep mechanism is the combined effect of the viscous flow of cement gel and the micro-damage caused by micro-cracks ( 9 , 10 ). Many scholars have also done relevant research on the potential factors that may affect concrete creep.…”

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confidence: 99%

Viscoelastic–Plastic Constitutive Model Considering the Damage Characteristics of Concrete in the Process of Nonlinear Creep

Shen

et al. 2021

Transportation Research Record: Journal of the Transportation R

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Under long-term load, the creep deformation of concrete materials has a serious impact on the structural safety of hydraulic structures, especially under the action of ultra-high stress levels, the concrete materials will undergo nonlinear creep, which is extremely easy to cause structural damage. In this study, the uniaxial nonlinear creep test of concrete specimens was used to establish the damage index based on the wave velocity value of ultrasonic flaw detection, and the creep and damage degree curve of the concrete specimen were obtained. The ideal elastic element, the Kelvin body, and the nonlinear viscoplastic element are connected in series, and a new viscoelastic–plastic model considering the creep characteristics of concrete is proposed. Based on the principle of least squares, the Levenberg–Marquardt (LM) algorithm is used to inverse the parameters of the nonlinear creep test. In addition, the model is verified by the measured data of linear creep. At the same time, the sensitivity of each model parameter is analyzed. The research shows that the LM algorithm can give the fitting parameters of the model better and faster, and the fitting values of the model are similar to the experimental results. The sensitivity analysis of the parameters shows that the proposed model has good stability and good adaptability. The model has a more accurate description of the various stages of creep, and may be conveniently applied to concrete creep calculations in actual projects.

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“…The basic principle of DEM is to express the discontinuity as a group of rigid circle particles, and derive the movement trend of the entire discontinuity through the motion equation of the rigid particles (Potyondy et al 2007;Potyondy et al 2004). It has been widely used to simulate mechanical processes such as rock, concrete, and cemented material (Li et al 2021a;Song et al 2019). Different mesoscopic contact models can be assigned to the contact between rigid circle particles to express different macroscopic mechanical properties of the material, such as elasticity, plasticity, and viscosity.…”

Section: Numerical Simulationmentioning

confidence: 99%

Effects of width-height ratio and roof-floor strength on the mechanical characteristics of cemented gangue backfill pier-column

Ran

Elchalakani²,

Yao³

et al. 2022

Environ Sci Pollut Res

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Cemented gangue backfill pier-column (CGBP) is the essential supporting component of the goaf in partial backfill mining or constructional backfill mining for controlling the surface subsidence of coal mining. The height of CGBP has been determined by the thickness of the coal seam, and thus the width-height ratio and roof-floor strength directly affect the bearing capacity of CGBP under axial compression. Herein the effect of width-height ratio (1/3-1/1) on the mechanical characteristics of CGBP with different curing ages under uniaxial compressive was system studied through experiment, and the damage process was analyzed by ultrasonic equipment and DIC. Based on the experimental results and discrete element theory, a three-phase numerical model for CGBP was established, which considered the real aggregate shape and distribution and the mechanical characteristics of each phase. Then, the effects of the end friction coefficient and the strength ratio of roof-CGBP-floor combination on the strength and failure characteristics of CGBP (large width-height ratio: 1/1-4/1) were investigated. The results show that: CGBP shows the width-height ratio effect obviously and the strength and ductility increase with the increase of the width-height ratio, and the widthheight ratio effect increases with the increase of curing age and strength ratio. The end friction constraint is the main reason for the width-height ratio effect, and the higher the friction coefficient is, the larger the width-height ratio effect shows, and the width-height ratio effect disappears without end friction constraint. The increase of the width-height ratio of CGBP and the strength ratio of the roof-CGBP-floor combination increases the strength of the combination.Whether the strength of the combination is greater than that of CGBP may have a roof-floor strength threshold or a strength ratio threshold, which are between 31. respectively. When the strength of the roof and floor is different, the strength of the combination is mainly controlled by the weak carrier and increases with the increase of the strength of the weak carrier. The peak strain energy of CGBP and combination increases with the increase of end friction coefficient, width-height ratio, and strength of roof and floor.

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Verification of concrete nonlinear creep mechanism based on meso-damage mechanics

Cited by 23 publications

References 20 publications

Failure properties and stability monitoring of strip and column cemented gangue backfill bodies under uniaxial compression in constructional backfill mining

Failure properties and stability monitoring of strip and column cemented gangue backfill bodies under uniaxial compression in constructional backfill mining

Viscoelastic–Plastic Constitutive Model Considering the Damage Characteristics of Concrete in the Process of Nonlinear Creep

Effects of width-height ratio and roof-floor strength on the mechanical characteristics of cemented gangue backfill pier-column

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