Experimental study on mechanical properties and failure behaviour of the pre-cracked coal-rock combination

Liu, Jiangwei; Wu, Na; Si, Guangyao; Zhao, Mingxin

doi:10.1007/s10064-020-02049-6

Cited by 38 publications

(8 citation statements)

References 20 publications

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“…In the study on the mechanical damage law of rocks with prefabricated cracks, Gratchev et al promoted uniaxial compression tests on three types of rock samples with cracks of different sizes, and it was concluded that the length and width of rock joints were important parameters affecting the strength of rock mass [ 5 ]. Liu et al made prefabricated cracks in the roof mudstone, studied the effect of prefabricated crack angle and size on the mechanical properties and failure mode of coal-rock combination samples, and concluded that the parameters of prefabricated cracks in the roof rock have an important influence on the effect of roof weakening [ 6 ]. Cao et al researched the crack propagation and evolution law of rock with two and three prefabricated crack defects with the help of indoor tests, and determined seven crack penetration modes according to the different inclination of rock bridge [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Study on the influence of hole defects with different shapes on the mechanical behavior and damage law of coal and rock

et al. 2022

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To study the effect of different shapes of hole defects in coal and rocks on their mechanical behavior and macro damage law, the microscopic mechanical parameters required for particle flow code (PFC) simulation were calibrated with laboratory test data, and then the evolution process of crack and stress field in coal and rocks with circle, square, triangular and trapezoidal holes under uniaxial compression were researched. The findings indicate that: the existence of hole defects lowers the elastic modulus, peak stress, peak strain and other mechanical parameters of coal and rock, and the reduction degree is influenced by the shape of defect. Meanwhile, the existence of hole defects promotes the generation and evolution of meso-cracks in coal and rock. For coal and rock with hole defects, the crack initiation stress and expansion stress are less than those of intact coal and rocks. The crack initiation stress and expansion stress of coal and rocks with trapezoidal hole defects are the smallest, and the coal and rocks with circular hole defects are the largest. The existence of hole defects weakens the damage degree of coal and rocks to some extent. With the increase of axial strain, the evolution curve of the number of meso-cracks shows stage characteristics, which consists of the calm period before the crack initiation point, the stable growth stage between the crack initiation point and the dilatation point, and the accelerated growth stage after the dilatation point. Before the initiation of crack, the concentration zone of compressive stress is located on the left and right sides of the hole defect, and the concentration zone of tensile stress is located on the upper and lower sides of the hole defect. The concentration of tensile stress is the main reason for the initiation and propagation of cracks, while the existence of compressive stress chain among macroscopic cracks is the cause of the residual strength of coal and rocks after failure.

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Section: Introductionmentioning

confidence: 99%

Study on the influence of hole defects with different shapes on the mechanical behavior and damage law of coal and rock

et al. 2022

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“…Du and Wang et al [7] conducted conventional triaxial compression tests on gas-bearing coal, gas-bearing coal mudstone assemblage and gas-bearing coal sandstone assemblage using RLW-500G triaxial test system, and unloading tests on gas-bearing coal sandstone assemblage specimens to analyze the deformation and strength characteristics of different coal-rock assemblages and discuss their acoustic emission behaviors. Liu et al [8] investigated the effects of fracture length and angle on the mechanical properties and damage modes of the combined rock coal seams by uniaxial compression tests on 21 sets of combined rock coal specimens containing cracks.…”

Section: Introductionmentioning

confidence: 99%

Failure energy evolution of coal-rock combination with different inclinations

Liu

Yang

et al. 2022

Preprint

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In order to study the energy evolution characteristics and damage mechanism of coal-rock assemblages with different inclination angles in the process of deformation and damage under different circumferential pressures. The test results show that: the damage of the specimens is mainly caused by bevel shear damage and tensile damage; the deformation and damage of the coal rock assemblage are distributed as a negative exponential function of the inclination angle, and the change of the surrounding pressure has a significant effect on the energy; based on the brittleness index value of the coal rock assemblage, the evolution of the brittleness index and Based on the brittleness index values, the evolution law between the brittleness index and the inclination angle and the surrounding pressure of coal rock assemblage is explored, and the mechanism of the change of inclination angle in the deformation and damage of coal rock assemblage with different inclination angles on the plastic yielding degree, energy dissipation level, crack extension and fracture speed in the pre-peak stage is revealed.

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“…To analyze the deformation and strength characteristics of different coal–rock combinations and discuss their acoustic emission behaviors, Du and Wang et al 7 conducted conventional triaxial compression tests on gas-bearing coal, gas-bearing coal mudstone combination, and gas-bearing coal sandstone combination using RLW-500G triaxial test system, and unloading tests on gas-bearing coal sandstone combination specimens. Liu et al 8 investigated the effects of fracture length and angle on the mechanical properties and damage modes of the combined rock coal seams through uniaxial compression tests on 21 sets of combined rock coal specimens containing cracks. In order to investigate the influence of combination mode on the mechanical properties and damage characteristics of coal–rock combinations, Zhang et al 9 conducted uniaxial compression and triaxial compression test studies on rock-coal–rock, rock-coal and coal–rock combination specimens using the MTS815 rock mechanics system.…”

Section: Introductionmentioning

confidence: 99%

Failure energy evolution of coal–rock combination with different inclinations

Liu

Yang

et al. 2022

Sci Rep

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In this paper, in the deformation and damage process under different confining pressures, the energy evolution characteristics and damage mechanism of coal–rock combinations with different inclination angles are studied. Based on the brittleness indexes of coal rock combinations, the evolution rules between brittleness indexes and the inclination are explored, as well as the confining pressure of coal rock combinations; then, the influence mechanism of the inclination angle of coal rock combinations on the plastic yielding degree, energy dissipation level, crack extension and fracture speed in the pre-peak stage is revealed. The composite specimens are mainly damaged due to oblique shear and accompanied by tensile damage; In the deformation and damage, various energies of coal rock composites are distributed as a negative exponential function of the inclination angle, which is significantly affected by the change of the confining pressure.

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Experimental study on mechanical properties and failure behaviour of the pre-cracked coal-rock combination

Cited by 38 publications

References 20 publications

Study on the influence of hole defects with different shapes on the mechanical behavior and damage law of coal and rock

Study on the influence of hole defects with different shapes on the mechanical behavior and damage law of coal and rock

Failure energy evolution of coal-rock combination with different inclinations

Failure energy evolution of coal–rock combination with different inclinations

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