Effects of Accumulated Damage on the Dynamic Properties of Coal Measures Sandstone

Sha, Ziheng; Pu, Hai; Xu, Junce; Ni, Hong-Yang; Guo, Shiru

doi:10.3390/min12070810

Cited by 5 publications

(1 citation statement)

References 38 publications

(54 reference statements)

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“…It is important to mention that before each acoustic emission test, it is necessary to detect the noise level of the testing environment to set an appropriate acoustic emission threshold. Finally, the immersed specimens were microscopically scanned with an SEM electron microscope [23].…”

Section: Experimental Methodsmentioning

confidence: 99%

Experimental Study on the Physical and Mechanical Properties of Cemented Gangue Backfill under Acid Mine Water Erosion

Liu,

Pu,

et al. 2023

Applied Sciences

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Ensuring the structural safety of cemented gangue backfill (CGB) is crucial for safe mining operations. However, the complex mine water environment makes it susceptible to erosion by chemical ions, which have a significant time dependency. In this study, we evaluated the appearance, mass change, and unconfined compressive strength (UCS) of CGB during different chemical erosion times. We also determined the effect of chemical ion erosion time on the stress threshold for crack initiation and development in the specimens using acoustic emission (AE). Additionally, we examined the chemical erosion mechanism of CGB by scanning electron microscopy (SEM). Our results showed that as the erosion time increased, the CGB exhibited a decrease in brittleness and an increase in plasticity. During the first 60 days of CGB, the internal micropores and microfractures of the CGB were filled due to the hydration reaction and SO42− intrusion, resulting in increases in the UCS and the mass of the CGB. However, as the erosion time continued, H+ and SO42− intruded into the interior of the CGB, causing the erosion products of the CGB to expand in volume, leading to a decrease in the strength of the CGB. Our analysis of the stress thresholds for microcrack development and macrocracks initiation in the CGB showed an increase followed by a decline with time. After 60 days of immersion, the stress threshold for microcrack initiation and macrocrack extension increased by 20% and 6%, respectively. However, as the immersion time increased to 150 days, the stress threshold for microcrack initiation and macrocrack extension decreased by 56% and 16%, respectively. Therefore, the design of CGB safety needs to consider the long-term effects of chemical attacks on CGB.

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Section: Experimental Methodsmentioning

confidence: 99%

Experimental Study on the Physical and Mechanical Properties of Cemented Gangue Backfill under Acid Mine Water Erosion

Liu,

Pu,

et al. 2023

Applied Sciences

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Study on the Cyclic Impact Mechanical Characteristics of Coal under Confining Pressure

Yongliang,

Liying,

Xuegang

2024

ACS Omega

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Coal damage accumulation and strength deterioration caused by mining-induced disturbances in deep mines are among the factors influencing the occurrence of dynamic disasters such as rock bursts. To study the mechanical deformation and failure characteristics of coal masses under both cyclic impact and confining pressure, SHPB experiments were performed to systematically analyze the behavior of coal samples under 1, 2, and 3 cycles at impact pressures of 0.25, 0.30, 0.35, 0.40, and 0.45 MPa. To study the influence of pressure and impact frequency on the dynamic mechanical failure of coal samples, a weakening effect model of coal samples under confining pressure was established, revealing the dynamic mechanical characteristics and failure mechanism of coal samples under different impact pressures and impact frequencies. The confining pressure SHPB results reveal that the number of cycles and impact pressure are inversely proportional to the peak stress and are proportional to the degree of weakening. The peak stress weakening coefficient of the coal samples under the different impact pressures ranged from 28.5 to 73.2%, and a linear weakening relationship with the number of cycles was obtained. The coal exhibited an end effect-controlled Y-shaped failure mode under both confining pressure and dynamic loading. This study provides an experimental reference for preventing the energy absorption and erosion of weak structures around rock bursts and improving the stability of supporting structures.

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Research on dynamic mechanical properties and damage model of ceramic materials under multi‐axial stress

Kong,

Yao,

Wang

2024

Int J Applied Ceramic Tech

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Due to their exceptional impact resistance, ceramics are extensively used in various fields. However, unavoidable pores, microcracks, and inherent defects can degrade the performance of ceramic materials. A damage model of SiC ceramics under passive confining pressure was constructed based on the Lemaitre strain equivalence principle and the Weibull distribution function. This paper presented a dynamic damage model for SiC ceramics subjected to passive confinement pressure based on the principles of damage mechanics. Additionally, the split Hopkinson pressure bar device was employed to investigate the compressive strength and damage evolution of SiC ceramics at various shock pressures and confinement degrees. The experimental results indicate that constraints can reduce the damage to ceramics. The metal sleeve increased stiffness when compressing the ceramic material, allowing the specimen to convert from brittle–plastic–brittle. When sufficient constraints can be provided, the peak strain decreases gradually with the increase of the impact air pressure. Experimental data showing good agreement with the proposed model validated and analyzed the established model. Thinner boundary constraints cannot maintain the stability of ceramic structures, thicker boundaries do not significantly improve performance, and thicker boundaries can cause more weak areas. This paper provides guidance for the design of encapsulated ceramic composite armor by quantitatively studying the constraint thickness.

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Effects of Accumulated Damage on the Dynamic Properties of Coal Measures Sandstone

Cited by 5 publications

References 38 publications

Experimental Study on the Physical and Mechanical Properties of Cemented Gangue Backfill under Acid Mine Water Erosion

Experimental Study on the Physical and Mechanical Properties of Cemented Gangue Backfill under Acid Mine Water Erosion

Study on the Cyclic Impact Mechanical Characteristics of Coal under Confining Pressure

Research on dynamic mechanical properties and damage model of ceramic materials under multi‐axial stress

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