Damage Characteristics and Constitutive Model of Deep Rock under Frequent Impact Disturbances in the Process of Unloading High Static Stress

Chun, Wang; Zhan, Shuai-fei; Xie, Minzhu; Cheng, Lu-ping; Xiong, Zuqiang

doi:10.1155/2020/2706091

Cited by 11 publications

(12 citation statements)

References 43 publications

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“…Damage mechanics is the study of the material properties of the damaged medium, and the mechanical process of damage evolution and development until failure during deformation 1 . Many scholars use different parameters to study the rock damage process, such as the number of rock cracks 2,3 , strain [4][5][6] , energy evolution 7 , and acoustic emission signal parameters 6,8 .…”

Section: Introductionmentioning

confidence: 99%

“…In formula (5), the value of N c is the cumulative acoustic emission ringing counts of the whole process of rock sample compression failure, and the value of N d is the cumulative acoustic emission ringing counts of each stage in the progress of rock sample compression failure. In order to simplify the calculation, Liu et al ( 2009) normalized the damage critical value according to the method of linear function conversion, and obtained 6 Where: σ p is the peak strength, σ c is the residual strength.…”

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confidence: 99%

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Study on acoustic emission characteristics and damage evolution of shale under uniaxial compression

Chan

et al. 2023

Preprint

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Acoustic emission tests under uniaxial compression of shale were carried out by using MTS815 rock servo test system and PCI-2 acoustic emission system. The law of acoustic emission and its damage evolution characteristics are analyzed and a uniaxial compression damage constitutive model of shale based on acoustic emission characteristics is established. The research shows that: (1) The uniaxial compression process of shale can be divided into four stages: crack compaction stage - elastic stage to the stable development stage of micro-elastic fracture - unstable fracture development stage - post-rupture stage. The acoustic emission signals are less during crack compaction stage and elastic stage to the stable development stage of micro-elastic fracture. When the axial stress reaches the damage strength σcd, which is about 80% of the peak strength, a large number of acoustic emission signals begin to be generated. There will be a large number of acoustic emission phenomena in the unstable fracture development stage and post-fracture stage. (2) The acoustic emission signal can well reflect the internal damage and destruction process of shale. The damage factor D shows a trend of decreasing first and then increasing with the increase of acoustic emission cumulative ringing counts, rather than monotonically increasing. When the acoustic emission cumulative ringing counts and damage factor start to increase slowly, the corresponding stress can be regarded as the crack initiation strength σci. (3) The damage factor D is proportional to the cumulative acoustic emission ringing counts N. According to the acoustic emission characteristics of rock specimens at different stages, the relationship between the damage factor D and the acoustic emission cumulative ringing counts C at different stages is obtained by linear fitting using origin software, thus a more reasonable shale damage constitutive model is established. In this way, the theoretical stress-strain curve obtained by the damage constitutive model is more consistent with the actual stress-strain curve.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Study on acoustic emission characteristics and damage evolution of shale under uniaxial compression

Chan

et al. 2023

Preprint

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“…Lemaitre (1984) introduced the strain equivalence assumption, which provides a theoretical framework for developing damage models with the static elastic modulus as an evaluation index. Wang et al (2020) used the static elastic modulus to present the damage evolution of rock under cyclic loading. (2) Porosity damage model: The porosity test for rocks generally includes oven-drying and nuclear magnetic resonance tests (Ke et al 2017;Li et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Study on a Damage Model and Uniaxial Compression Simulation Method of Frozen–Thawed Rock

et al. 2021

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To evaluate the deterioration degree of rock freeze-thaw damage in cold area engineering, it is necessary to establish an accurate freeze-thaw rock damage model and its uniaxial compression numerical simulation method. Therefore, indoor freeze-thaw cycle tests of saturated yellow sandstone were carried out. The porosity and P-wave velocity were measured, and uniaxial compression tests were conducted after different numbers of freeze-thaw cycles. The findings indicate that with an increasing number of freeze-thaw cycles, the elastic modulus, peak strength and wave velocity of the yellow sandstones gradually decrease, while the peak strain and the average porosity increase. The energy evolution law with different numbers of freeze-thaw cycles was analyzed, a freeze-thaw damage model was established according to the relative change in the dissipated energy ratio before and after freezing-thawing, and the accuracy of this damage model and five common damage models was evaluated by the uniaxial compressive strength and peak strain. The functional relationship between mesoscopic parameters and the number of freeze-thaw cycles was formulated to establish a numerical simulation method for saturated sandstones under uniaxial compression after freeze-thaw cycling. The reliability of the numerical method was verified by comparing the stress-strain curve, peak stress, peak strain and energy law with the experimental results.

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“…Wang et al defined damage variables of the rock by continuous factors, strain equivalence principle, and statistical damage theory. They also established a damage constitutive model of rock under frequent disturbances in the process of unloading high static stress [33]. Liu et al proposed an experimental method to obtain the stress and strain of coal in coal-rock combined samples and established two damage constitutive models of coal, which could accurately describe stress-strain curves of coal in coal-rock samples and reflect the influences of rock, coal-rock combination form, and coal-rock height ratio [34].…”

Section: Introductionmentioning

confidence: 99%

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

Zhang

Lin

et al. 2021

Geofluids

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The research on dynamic mechanical properties of rocks under high temperature is the basis for safe and efficient implementation of deep coal mining and underground coal gasification engineering. In this paper, the split Hopkinson bar (SHPB) with real-time high-temperature function was adopted to systematically study dynamic mechanical properties of sandstones. The research showed that under the condition of a fixed temperature, with the increase of strain rate, the dynamic compressive strength and dynamic peak strain of sandstone increased gradually, and the variation of dynamic elastic modulus with strain rate was not obvious. With the increase of temperature, the dynamic compressive strength of sandstone increased first and then decreased, the dynamic peak strain increased gradually, and the dynamic elastic modulus decreased overall. The variation law of macroscopic failure mode and energy dissipation density with temperature was revealed, and the change mechanism was explained considering the influence of high temperature on the internal structure of sandstone. Based on the principle of component combination and the theory of micro-element strength distribution, the dynamic statistical damage constitutive model was established, and its parameters had certain physical significance. Compared with the experimental results, the established model can well describe the dynamic stress-strain relationship of sandstone under real-time high temperature.

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Damage Characteristics and Constitutive Model of Deep Rock under Frequent Impact Disturbances in the Process of Unloading High Static Stress

Cited by 11 publications

References 43 publications

Study on acoustic emission characteristics and damage evolution of shale under uniaxial compression

Study on acoustic emission characteristics and damage evolution of shale under uniaxial compression

Study on a Damage Model and Uniaxial Compression Simulation Method of Frozen–Thawed Rock

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

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