Dynamic response and failure mechanism of fractured coal under different soaking times

Gu, Helong; Tao, Ming; Li, Xibing; Li, Qiyue; Cao, Wenzhuo; Wang, Fu

doi:10.1016/j.tafmec.2018.09.001

Cited by 35 publications

(15 citation statements)

References 33 publications

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“…Previous studies on water‐coal interaction focused on the mechanical properties of coal, which were induced by water intrusion. Gu et al studied the relationship between the dynamic response of coal and the effect of soaking times. Their results indicated that the compressive strength and Young's modulus both decreased gradually with increasing soaking time.…”

Section: Introductionmentioning

confidence: 99%

Influence of cyclic wetting‐drying on the mechanical strength characteristics of coal samples: A laboratory‐scale study

Chen

Jiang

Wang³

et al. 2019

Energy Science & Engineering

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Water‐coal interactions have gained much recent attention, although few studies focus on the strength of coal under wetting‐drying cycles. This study investigates changes in the microstructure and mechanical strength of coal that are induced by water‐coal interactions, at the macroscale and microscale. Fourteen specimens after continuous wetting and fourteen specimens after wetting‐drying cycles were tested, indicating that peak stress and elastic modulus decrease with increasing continuous wetting time and number of wetting‐drying cycles, while peak strain increases. We analyzed changes in the coal microstructure using a scanning electron microscope (SEM) and the Image Pro Plus 6.0 (IPP 6.0) software. The regression model for cyclic wetting‐drying reveals that porosity and pore circularity are the main correlation indicators associated with uniaxial compressive strength. Therefore, different numbers of wetting‐drying cycles could induce different degrees of damage to coal, which increases progressively through gradual changes to its microstructure. These findings indicate that wetting‐drying cycles have a more significant impact on the stability of coal mass than continuous wetting. Our results are of use in determining the size of coal pillars, and expanding the knowledge base related to the mechanical properties of coal mass, water bursting, water recharge channels, and the stress‐crack‐permeability evolution law in mines.

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Section: Introductionmentioning

confidence: 99%

Influence of cyclic wetting‐drying on the mechanical strength characteristics of coal samples: A laboratory‐scale study

Chen

Jiang

Wang³

et al. 2019

Energy Science & Engineering

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“…Zhao [9] studied coal's dynamic tensile failure characteristics in dry and saturated states, and found that saturated coal samples have higher tensile strength compared with dry coal samples. Gu [10,11] tested the static and dynamic mechanical properties of coal samples under different water-bearing conditions. The results showed that with the increase in water content, the static mechanical parameters of coal samples deteriorated to a certain degree, while the dynamic mechanical parameters increased first and then decreased.…”

Section: Introductionmentioning

confidence: 99%

Physical and Mechanical Properties Evolution of Coal Subjected to Salty Solution and a Damage Constitutive Model under Uniaxial Compression

et al. 2021

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Many underground reservoirs for storing water have been constructed in China’s western coal mines to protect water resources. Coal pillars which work as dams are subjected to a long-term soaking environment of concentrated salty water. Deterioration of the coal dam under the attack of the salty solution poses challenges for the long-term stability and serviceability of underground reservoirs. The evolution of the physical and mechanical properties of coal subjected to salty solutions are investigated in this paper. Coal from a western China mine is made to standard cylinder samples. The salty solution is prepared according to chemical tests of water in the mine. The coal samples soaked in the salty solution for different periods are tested by scanning electron microscope, nuclear magnetic resonance, and ultrasonic detector techniques. Further, uniaxial compression tests are carried out on the coal specimens. The evolutions of porosity, mass, microstructures of coal, solution pH values, and stress–strain curves are obtained for different soaking times. Moreover, a damage constitutive model for the coal samples is developed by introducing a chemical-stress coupling damage variable. The result shows that the corrosion effect of salty solution on coal samples becomes stronger with increasing immersion time. The degree of deterioration of the longitudinal wave velocity (vp) is positively correlated with the immersion time. With the increase in soaking times, the porosity of coal gradually increases. The relative mass firstly displays an increasing trend and then decreases with time. The peak strength and elastic modulus of coal decreases exponentially with soaking times. The developed damage constitutive model can well describe the stress–strain behavior of coal subjected to salty solution under the uniaxial compression.

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“…There has been extensive research on the properties of coal with different water content. Gu [4] found that the dynamic properties of coal samples are obviously affected by the water absorption time, considering three stages of the process with different water-coal interaction mechanisms of each stage. Perera [5] compared the strength and deformation characteristics of saturated and dry coal samples.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Tensile Strength of Dry and Saturated Hard Coal under Impact Loading

Zhu

Wei

et al. 2020

Energies

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To evaluate the influence of water content on the hard coal dynamic behavior, the dynamic tensile properties of saturated coal Brazilian disk (BD) samples were studied using a split Hopkinson pressure bar system, and dry samples were also tested as a control group. In the range of impact speeds studied, the tensile strength of the saturated coal is lower than that of the dry specimen. A synchronized triggering high-speed camera was used to monitor the deformation and failure process of dry and saturated coal samples, allowing analysis of the failure stages and mechanism of dynamic BD test, the broken mode was classified into three types, which can be classified into unilateral tensile failure, bilateral or multilateral tensile failure, and shear failure. Finally, fragments smaller than 5 mm in diameter were statistically analyzed. There is less debris in range of 0–5.0 mm for the saturated coal sample than for the dry coal. This study provides some information about the dynamic response of the hard coal for the relevant practical engineering.

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Dynamic response and failure mechanism of fractured coal under different soaking times

Cited by 35 publications

References 33 publications

Influence of cyclic wetting‐drying on the mechanical strength characteristics of coal samples: A laboratory‐scale study

Influence of cyclic wetting‐drying on the mechanical strength characteristics of coal samples: A laboratory‐scale study

Physical and Mechanical Properties Evolution of Coal Subjected to Salty Solution and a Damage Constitutive Model under Uniaxial Compression

Dynamic Tensile Strength of Dry and Saturated Hard Coal under Impact Loading

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