Controlling roof with potential rock burst risk through different pre-crack length: Mechanism and effect research

Zhao, Tianfeng; Zhang, Peng-Fei; Guo, Wei‐yao; Gong, Xufei; Wang, Chao; Chen, Yang

doi:10.1007/s11771-022-5190-7

Cited by 38 publications

(14 citation statements)

References 36 publications

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“…15,16 Furthermore, the angle between the loading direction and the joint planes has a significant impact on the mechanical property and crack style of jointed coal. 17 At the angle less than 45°, coal samples present slippage and tension cracks. Once the angle exceeds 45°, coal samples present friction-extrusion failure.…”

Section: Introductionmentioning

confidence: 99%

“…It has been widely reported that the anisotropy related to strength of the jointed coal sample under compression is determined by the distributions of fractures, pores and minerals. − When the compression direction is perpendicular to joint planes, both the compression strength and elastic modulus of coal are much higher than those of the coal sample with the loading direction parallel to the joint planes . When the loading direction is perpendicular to joint planes, the jointed coal samples are characterized by burst failure, whereas the samples under compression along joint planes mainly present plastic failure. , Furthermore, the angle between the loading direction and the joint planes has a significant impact on the mechanical property and crack style of jointed coal . At the angle less than 45°, coal samples present slippage and tension cracks.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of Acoustic Emission and Microcrack in Jointed Coal under Loading and Their Correlations

Wang,

Guan,

et al. 2023

ACS Omega

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Understanding of continuous damage and cracking process of compressed jointed coal is critical to predict its stability. Herein, for jointed coal under uniaxial compression with bedding planes perpendicular (sample A) and parallel (sample B) to the loading direction, an acoustic emission (AE) monitoring device and a computed tomography (CT) scanner were employed to study the damage and cracking process. Furthermore, the correlations between the AE signals and internal fracture parameters were analyzed. Results show that (1) shear and tension cracks are respectively main damage forms in samples A and B; (2) there is a drop valley of variations of AE count fractal dimension (D 1) over time before the stress peak, and compared with sample B, the drop valley for sample A are much wider; (3) many fractures between joint planes formed at yielding and postpeak stages, fracture fractal dimensions (D 2) first increase slightly with loading and then increase significantly at yielding and postpeak stages; especially D 2 of sample A is larger than that of sample B; (4) the accumulative value of D 1 (AD 1) increases with D 2 monotonously, and an expression of porosity or connectivity of the compressed jointed coal was developed, by which the porosity and connectivity of jointed coal could be calculated. The study outcomes could contribute to predict coal stability and the variations of water and gas flowing channels in seam in underground coal mines.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evolution of Acoustic Emission and Microcrack in Jointed Coal under Loading and Their Correlations

Wang,

Guan,

et al. 2023

ACS Omega

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“…Over the last decades, some researchers have made important contributions to the cracking behavior of concrete structures, crack distribution mode, crack width, and section stress distribution, as well as ordinary steel bar stress at the cracks [10][11][12][13][14][15][16]. For small-and medium-span bridges, simply supported RC beams (such as hollow plates or T-beams) are widely used in practical engineering [17,18].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation and Theoretical Prediction Model of Flexural Bearing Capacity of Pre-Cracked RC Beams

Zhou

Yan

2023

Applied Sciences

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Cracking is one of the main diseases of small- and medium-span reinforced concrete (RC) bridges. It is a key problem to determine the change in mechanical properties of RC beams after cracking in bridge-performance evaluation. The present study performs static loading tests on seven simply supported T-beams with different crack damage conditions. The influences of crack location, crack depth and steel-bar diameter at a prefabricated crack on the stress, deflection and crack distribution pattern of pre-cracked test beams are investigated. The failure mode and mechanism of pre-cracked beams are revealed. Based on the experimental results, a finite element model of a pre-cracked beam is developed and validated. Following this, a theoretical prediction method is proposed to calculate the ultimate load of pre-cracked RC beams. The results indicate that the direct damage to mid-span section size can significantly affect the stiffness of the RC beam. The local damage of the tensile steel section has insignificant influence on the overall stiffness of the beam. The stiffness degradation of the pre-cracked beam at the quarter span is smaller than that of the pre-cracked beam at mid-span. The strain of the T-beam section in the pre-cracked test conformed to the assumption of the flat section. The experimental observations are in good agreement with the theoretical predictions, which can provide a theoretical basis for the performance evaluation of existing RC beams.

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“…[11][12][13] In addition to analyzing the mechanical properties of the rock itself, some scholars have used acoustic emission (AE), digital speckle (DIC), infrared photography, electromagnetic radiation, and other methods to analyze precursor information, such as acoustic and electric heating, that leads to the instability of fractured rock. [14][15][16][17][18] In engineering projects, natural rock cracks often contain soft mud, sand, and other fillings; however, the fractured rock can also be filled artificially and reinforced with grouting to repair a rock layer damaged by mining. 19 Although relevant experimental studies have been conducted using fracture-filled rocks to analyze the influence of fracture filling on specimen strength and post-peak plastic deformation, [20][21][22] research on the basic mechanical properties and failure mechanism of fracturefilled rock is insufficient.…”

Section: Introductionmentioning

confidence: 99%

“…Some scholars have studied the influence of the lateral pressure coefficient and confining pressure on the mechanical behavior and crack growth mode of fractured rock and further revealed its failure mechanism 11–13 . In addition to analyzing the mechanical properties of the rock itself, some scholars have used acoustic emission (AE), digital speckle (DIC), infrared photography, electromagnetic radiation, and other methods to analyze precursor information, such as acoustic and electric heating, that leads to the instability of fractured rock 14–18 …”

Section: Introductionmentioning

confidence: 99%

The influence of infilling material strength on mechanical properties and failure mechanism of fractured sandstone

Zhang,

Wang,

Guo

et al. 2023

Fatigue Fract Eng Mat Struct

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To reveal the failure mechanism of fractured sandstone under the influence of the infilling material strength, uniaxial compression tests, and PFC3D numerical simulation analyses were conducted on fractured sandstone with different infilling material strengths, and the influence of the infilling material strength on the basic mechanical properties of the fracture‐filled sandstone was studied. The results showed that, with increasing infilling material strength, the peak strength and elastic modulus of the specimens increased nonlinearly and eventually stabilized. The failure pattern of the specimens changed from shear to tensile. When the infilling material strength was low, a wing crack or anti‐wing crack was generated; however, when the infilling material strength was high, a vertical tensile crack was generated. From the perspective of fracture mechanics, the filling of sandstone cracks can reduce or even suppress the stress concentration effect at the prefabricated crack tip and improve the bearing capacity of the fractured sandstone.

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Controlling roof with potential rock burst risk through different pre-crack length: Mechanism and effect research

Cited by 38 publications

References 36 publications

Evolution of Acoustic Emission and Microcrack in Jointed Coal under Loading and Their Correlations

Evolution of Acoustic Emission and Microcrack in Jointed Coal under Loading and Their Correlations

Experimental Investigation and Theoretical Prediction Model of Flexural Bearing Capacity of Pre-Cracked RC Beams

The influence of infilling material strength on mechanical properties and failure mechanism of fractured sandstone

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