Analysis of the Dynamic Impact Mechanical Characteristics of Prestressed Saturated Fractured Coal and Rock

Wen, Wang; Zhang, Shiwei; Li, Huamin; Gong, Shuang; Liu, Zhumeng

doi:10.1155/2019/5125923

Cited by 12 publications

(12 citation statements)

References 21 publications

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“…Under coupled static and dynamic loads, in the process of applying axial static preload, a certain amount of elastic strain energy had been deposited inside the limestone specimen, which should be considered in the calculation method [37,38].…”

Section: Energy Dissipation Analysis Of Limestonementioning

confidence: 99%

Coupled Static‐Dynamic Tensile Mechanical Properties and Energy Dissipation Characteristic of Limestone Specimen in SHPB Tests

Ping

Fang

et al. 2020

Advances in Civil Engineering

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To investigate the dynamic splitting tensile mechanical property of limestone under coupled static and dynamic state, the dynamic split tensile tests of limestone under one-dimensional coupled static and dynamic load with different strain rates were performed with the help of modified split Hopkinson pressure bar (SHPB) equipment. The dynamic splitting tensile mechanical property and energy dissipation characteristic under two stress states were also compared in this research. Test results indicated that the dynamic tensile strength of the limestone specimen increased with the increase of average strain rate, exhibiting an obvious strain rate effect. In addition, dynamic tensile strength under uniaxial state was higher than that under one-dimensional coupled static and dynamic load state under the same test condition. Moreover, the deformation modulus increased with increasing average strain rate under uniaxial state, while it decreased with increasing average strain rate under coupled static and dynamic state. Both the reflected energy and absorbed energy linearly increased with increasing incident energy. The preload in the radial direction could increase the reflected energy and decrease the absorbed energy. Moreover, the transmitted energy with preload state was slightly lower than that under uniaxial state. Finally, the dynamic tensile strength of limestone specimen increased as a power function with increasing absorbed energy.

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Section: Energy Dissipation Analysis Of Limestonementioning

confidence: 99%

Coupled Static‐Dynamic Tensile Mechanical Properties and Energy Dissipation Characteristic of Limestone Specimen in SHPB Tests

Ping

Fang

et al. 2020

Advances in Civil Engineering

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“…erefore, the influence of water content on the mechanical properties of coal under complex stress conditions cannot be ignored. Wang et al [29] found that the strengths of coal specimens saturated for seven days are 52% lower than those of natural coal specimens. Gu et al [30] proposed a constitutive model considering the damage by water to describe the deformation of coal.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on the Influence of Water Content on the Mechanical Properties of Coal under Conventional Triaxial Compression

Zhang

Rongshan

2020

Shock and Vibration

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The presence of water is one of the most important factors in coal mining, and it has a dual influence on the mechanical behavior of rock. To study the influence of water content on the mechanical properties of coal under complicated stress conditions, dry coal specimens and wet coal specimens with water contents of 1.8% and 3.6% were conducted by uniaxial and conventional triaxial compression tests. The relations between the uniaxial compressive strength, deformation, and water content were observed. The reductions in the strength and elastic modulus under different confining pressures were obtained. The mechanical properties of coal specimens with different water contents under triaxial compression were studied. The influences of water content on the microstructure, clay minerals, internal friction angle, and cohesive force of coal were discussed. The results show that the strengths and elastic moduli of wet specimens are clearly lower than those of dry specimens under different confining pressures. The water content has a significant influence on the postfailure mechanical behavior of coal. The loss rates of strength and elastic modulus decrease with increasing confining pressure. The water content has almost no effect on the internal friction angle, while the cohesive force of the saturated specimens is 36.5% lower than that of the dry specimens. The results can provide a reference for inhibiting the occurrence of disasters during coal mining and exploiting coal efficiently.

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“…Massive efforts have been made to explore the effect of water on the mechanical properties of coal [17][18][19][20][21][22][23][24][25][26]. For example, White and Mazurkiewicz [17] conducted uniaxial compressive tests on Nemo coal specimens with different water contents.…”

Section: Introductionmentioning

confidence: 99%

Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions

2020

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Underground coal mines are frequently subjected to water infusion, resulting in many mining hazards. This study investigated the effect of water infusion on the stress and energy evolution characteristics of coal specimens representing isolated pillars under different initial axial stress conditions using the discrete element method. A water infusion distribution model was developed, in which random functions were employed to describe water distribution for the purpose of realizing the dispersion of results for a better reliability. Based on the results, a stress-level classification was presented to evaluate the water effect on pillars’ instability. For the investigated coal specimens, the water weakening effect on stress and energy remains stable when the axial geo-stress on pillars is less than 65% of uniaxial compressive strength (UCS). In contrast, when the axial stress coefficient is greater than 65%, pillars become unstable eventually. A higher axial stress coefficient is more likely to introduce a lower critical instability point of the water saturation coefficient for pillars in the process of water infusion. However, the instability point remains random to some extent for specimens following the same water distribution rule under the identical test condition. Two instability types, which also happened randomly, were observed in the numerical results for damaged coal specimens under different water saturation coefficients and axial geo-stresses, namely free-falling and step-falling.

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Analysis of the Dynamic Impact Mechanical Characteristics of Prestressed Saturated Fractured Coal and Rock

Cited by 12 publications

References 21 publications

Coupled Static‐Dynamic Tensile Mechanical Properties and Energy Dissipation Characteristic of Limestone Specimen in SHPB Tests

Coupled Static‐Dynamic Tensile Mechanical Properties and Energy Dissipation Characteristic of Limestone Specimen in SHPB Tests

Experimental Investigation on the Influence of Water Content on the Mechanical Properties of Coal under Conventional Triaxial Compression

Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions

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