A coupled elastoplastic anisotropic damage model for rock materials

Wang, Susheng; Xu, Weiya

doi:10.1177/1056789520904093

Cited by 19 publications

(6 citation statements)

References 49 publications

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“…Rocks may gradually accumulate damage deformation under external load, causing severe plastic deformation or even progressive failure (Krajcinovic et al, 1991;Liu et al, 2020;Su et al, 2019;Wang and Xu, 2020;Wu et al, 2019). The deformation and failure processes of rock, with many cracks and voids, are accompanied by energy release in the form of vast elastic waves (Ebrahimian et al, 2019;Feng et al, 2020;Hu et al, 2019;Wang et al, 2015;Xu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Study on mechanical properties and damage evolution of carbonaceous shale under triaxial compression with acoustic emission

Yang

Yan

Zhang

et al. 2021

International Journal of Damage Mechanics

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To explore the mechanical properties and damage evolution characteristics of carbonaceous shale with different confining pressures and water-bearing conditions, triaxial compression tests accompanied by simultaneous acoustic emission (AE) monitoring were conducted on carbonaceous shale rock specimens. The AE characteristics of carbonaceous shale were investigated, a damage assessment method based on Shannon entropy of AE was further proposed. The results suggest that the mechanical properties of carbonaceous shale intensify with increasing confining pressure and degrade with increasing water content. Moisture in rocks does not only weaken the cohesion but also reduce the internal friction angle of carbonaceous shale. It is observed that AE activities mainly occur in the post-peak stage and the strong AE activities of saturated carbonaceous shale specimens appear at a lower normalized stress level than that of natural-state specimens. The maximum AE counts and AE energy increase with water content while decrease with confining pressure. Both confining pressure and water content induce changes in the proportions of AE dominant frequency bands, but the changes caused by confining pressure are more significant than those caused by water content. The results also indicate that AE entropy can serve as an applicable index for rock damage assessment. The damage evolution process of carbonaceous shale can be divided into two main stages, including the stable damage development stage and the damage acceleration stage. The damage variable increases slowly accompanied by a few AE activities at the first stage, which is followed by a rapid growth along with intense acoustic emission activities at the damage acceleration stage. Moreover, there is a sharp rise in the damage evolution curve for the natural-state specimen at the damage acceleration stage, while the damage variable develops slowly for the saturated-state specimen.

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Section: Introductionmentioning

confidence: 99%

Study on mechanical properties and damage evolution of carbonaceous shale under triaxial compression with acoustic emission

Yang

Yan

Zhang

et al. 2021

International Journal of Damage Mechanics

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“…7: where p is the plastic hardening variable and is the damage variable. Though a few studies proposed that the plastic and damage evolution are fully coupled (Salari et al 2004;Chen et al 2010;Wang and Xu 2020), based on the observation in Sect. 3.3, it is suggested that damage and plasticity are not so closely related.…”

Section: Constitutive Modellingmentioning

confidence: 99%

A Pre-peak Elastoplastic Damage Model of Gosford Sandstone Based on Acoustic Emission and Ultrasonic Wave Measurement

et al. 2022

Rock Mech Rock Eng

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The determination of internal material damage is always an arduous challenge. Non-destructive monitoring methods show great potential in quantitatively determining the internal material properties, whereas most of the studies relying on external observations remain in a qualitative stage. They either violate the basic thermodynamic assumptions or are difficult to guide engineering practice. In this paper, following the theory of continuum mechanics, an elastoplastic damage model based on non-destructive monitoring methods (i.e., acoustic emission and ultrasonic wave velocity measurement) has been developed. To capture the continuous and precise damage evolution inside rock mass, P wave velocity obtained by ultrasonic wave measurement was utilised and then considered as an input for the proposed elastoplastic damage model. Triaxial loading test results on six Gosford sandstone samples were analysed first to characterise critical stresses along the stress–strain loading curves, such as crack closure stress, stable crack propagation stress and unstable crack propagation stress. The drop of ultrasonic wave velocity can be seen as an indicator to represent the damage evolution inside rock material. Damage initiation is also closely related to the confining stress and dilation induced volumetric expansion. The test results also suggested that the Drucker–Prager criterion is sufficient to describe the plastic yielding surface and the following material hardening. A non-associated plastic flow assumption was adopted, considering the essence of microcrack shearing in rock failure and the effect of hydrostatic pressure on plastic deformation. A modified Drucker–Prager plastic potential was also introduced to track the orientation of plastic increment with material hardening. A scalar damage variable was derived from ultrasonic wave measurement results to indirectly represent the deterioration of rock properties (modulus). The proposed model was used to match lab test results with high consistency, and the main features of rock behaviour in triaxial loading tests were successfully captured by the model. Finally, the damage evolution of rock samples was analysed, which indicates that damage is dependent on its conjugate force, namely damage energy release rate Y. This study proves that P wave velocity can be an effective approach to measure and forecast the internal damage evolution inside rock mass, which has broad prospects for engineering applications.

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“…Several factors including F-T duration, F-T cycle and F-T temperature have also influence the mechanical behaviors of rock. For freeze-thawed rocks, several damage evolution models, using the uniaxial compressive strength (UCS) (Takarli et al, 2008), elastic modulus (Takarli et al, 2008;Wang and Xu, 2020), porosity (Zhang et al, 2018), P-or S-velocities (Hori and Morihiro, 1998), acoustic emission activities (Tian et al, 2021), rock strain (Li et al, 2020), and mass loss rate (Nicholson and Nicholson, 2000;Zhang et al, 2018), have been proposed to describe the F-T fatigue damage. However, almost all those studies are focused on intact rock subjected to freezethaw treatment, and the freeze-thaw responses of the naturally fractured rocks are not well understood.…”

Section: Introductionmentioning

confidence: 99%

A strain-based fatigue damage model for naturally fractured marble subjected to freeze-thaw and uniaxial cyclic loads

Wang

Zhang

et al. 2021

International Journal of Damage Mechanics

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The naturally fractured rock in the open pit slope is susceptible to irreversible damage caused by fatigue loads related to freeze-thaw weathering, blasting vibration, earthquakes and tramcar traffic. To ensure the safety of rock mass and reveal how natural fracture affects the damage modelling characteristics is of great concern. Hence, this work aims at investigating the fatigue damage evolution of rock from volumetric deformation caused by F-T and cyclic loads. The rock structural deterioration and damage accumulation were investigated as well as the stimulated natural fracture pattern. Results show the frost heaving force acted on natural fracture results in the rock volumetric changes. The damage variable expressed by volumetric strain presents a linear relationship with freeze-thaw cycles. In addition, the axial, lateral and volumetric strain of marble exposed to cyclic loads present a two-stage pattern, they first increase quickly and then get to steady and last for a long time. A new fatigue damage model was established by considering the freeze-thaw damage and mechanical damage simultaneously. The proposed coupling damage model can well describe rock damage accumulation. Moreover, the CT images further reveal the influence of the natural fracture on rock volumetric deformation and the final damage accumulation. It is suggested that the opening-mode natural fractures contribute a lot to rock freeze-thaw deformation and fatigue deformation.

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A coupled elastoplastic anisotropic damage model for rock materials

Cited by 19 publications

References 49 publications

Study on mechanical properties and damage evolution of carbonaceous shale under triaxial compression with acoustic emission

Study on mechanical properties and damage evolution of carbonaceous shale under triaxial compression with acoustic emission

A Pre-peak Elastoplastic Damage Model of Gosford Sandstone Based on Acoustic Emission and Ultrasonic Wave Measurement

A strain-based fatigue damage model for naturally fractured marble subjected to freeze-thaw and uniaxial cyclic loads

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