Experimental study on evolution in the characteristics of permeability, deformation, and energy of coal containing gas under triaxial cyclic loading‐unloading

Chu, Yapei; Sun, Haitao; Zhang, Dongming

doi:10.1002/ese3.417

Cited by 37 publications

(14 citation statements)

References 16 publications

(26 reference statements)

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“…In fact, the absorption and transformation of energy is the essential cause of rock material failure. [15][16][17][18]. Especially in the dynamic test, the incident energy carried by the incident wave provides the energy source for the failure of rock specimens.…”

Section: Introductionmentioning

confidence: 99%

Energy Dissipation Characteristic of Red Sandstone in the Dynamic Brazilian Disc Test with SHPB Setup

Gong

2020

Advances in Civil Engineering

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In order to quantitatively investigate the energy dissipation characteristic during the dynamic tension failure of rock materials, the dynamic Brazilian disc tests on red sandstone were conducted using the split Hopkinson pressure bar (SHPB) setup. The states of the specimens after different incident energies can be divided into three forms (i.e., the unruptured state, the ruptured state, and the broken state), and the failure processes of the specimens were recorded by using a high-speed camera. The results show that the ruptured state of the specimen corresponds to the critical failure strain. Taking the critical incident energy as a turning point, two positive linear fitting relations between the dissipated energy and incident energy before and after the point are obtained, and the dynamic linear dissipation law is found. When the incident energy is less than the critical energy, specimens were unruptured after impact. When the incident energy is greater than the critical energy, specimens will be broken after impact. According to the obtained linear energy dissipation law, the dynamic tensile energy dissipation coefficient (DTEDC) was introduced for quantitatively describing the dynamic energy dissipation capacity of rock materials in the dynamic Brazilian disc test. When the specimen is in the unruptured state, the ideal DTEDC is a constant value. When the specimen is in a broken state, the DTEDC increases with the increase of incident energy.

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Section: Introductionmentioning

confidence: 99%

Energy Dissipation Characteristic of Red Sandstone in the Dynamic Brazilian Disc Test with SHPB Setup

Gong

2020

Advances in Civil Engineering

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“…The failure processes of intact coal samples and coal samples with different prefabricated fractures are dominated by different mechanical mechanisms and show different failure modes macroscopically. Although some researchers have conducted more studies on the mechanics and the permeability characteristics of coal under different cyclic loading and unloading paths, − the systematic studies on the constant amplitude cyclic loading and unloading with the pre-peak confining pressure are not enough, and further research studies are necessary.…”

Section: Introductionmentioning

confidence: 89%

Experimental Study on the Evolution Trend of the Pore Structure and the Permeability of Coal under Cyclic Loading and Unloading

Xin

Wang

et al. 2021

ACS Omega

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In the deep mining process of coal seams, the mechanical environment of the coal body is complex and in the state of cyclic loading and unloading. The change in the stress state leads to the change in the pore characteristics and the permeability. To investigate the effects of cyclic loading and unloading on the pore characteristics and the permeability of coal, the seepage experiment was carried out for the coal samples using the self-developed triaxial permeation instrument. By pressure confining and continuous cyclic loading and unloading, the evolution of the porosity and the permeability of the coal samples was investigated. Under the condition of the experiment, the influences of the initial value of the confining pressure and the cyclic load amplitude on the evolution of the permeability and the pore structure characteristics of the coal samples were clarified. The experimental results showed that the porosity and the permeability decreased exponentially with an increase in the number of loading and unloading cycles, and this decreasing trend gradually weakened until the porosity and the permeability became relatively stable. When the cyclic load amplitude was the same and the confining pressure increased, the effective porosity of the coal body and the bound porosity decreased. When the confining pressure was the same and the cyclic load amplitude increased, the effective porosity of the coal body decreased and the bound porosity increased. The loss rate of the permeability of the coal samples increased gradually with an increase in the cyclic load amplitude. The same tendency was observed when the cyclic load amplitude was the same, and the confining pressure was different, while the increasing trend was not so obvious. By analyzing the relationship between the porosity and the permeability of the coal samples under different cyclic loading and unloading paths, it was found that the effective porosity and the permeability of the coal samples conformed to the power–law relationship in the process of cyclic loading and unloading, and the change in the cyclic load amplitude had a significant effect on this relationship. The influences of the cyclic load amplitude and the confining pressure on the stress sensitivity of the coal samples were considered, and the change factor of the stress sensitivity was introduced into the relationship between the porosity and the permeability. This relationship was established considering cyclic loading and unloading.

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“…According to the law of energy conservation, coal and rock are bound to accumulate and dissipate energy during the entire process. 93 Although there are some models of coal and rock based on the energy accumulation and depletion in previous studies, they both neglected the initial accumulate and dissipate energy of coal and rock under the sampling environment before the tests. Therefore, it is suggested that based on fully relying on the continuous improvement advantages of the accuracy for the permeability test of (bedded) coal and rock, the permeability-energy evolution model need to be established considering the initial high in situ stress reduction (see Figure 11), to indirectly quantify the energy accumulation and dissipation of coal and rock in the entire process.…”

Section: Permeability Propertiesmentioning

confidence: 99%

“…However, coal and rock will inevitably be accompanied by a series of evolution processes such as compaction, deformation, damage, and failure under stress‐seepage coupling. According to the law of energy conservation, coal and rock are bound to accumulate and dissipate energy during the entire process 93 . Although there are some models of coal and rock based on the energy accumulation and depletion in previous studies, they both neglected the initial accumulate and dissipate energy of coal and rock under the sampling environment before the tests.…”

Section: Permeability Propertiesmentioning

confidence: 99%

The permeability properties of bedded coal and rock: Review and new insights

Song

Zhang

et al. 2022

Energy Science & Engineering

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It is beneficial to understand deeply the permeability properties of coal and rock for the stability control of mining engineering, underground engineering, oil and gas engineering, nuclear waste storage engineering, and so on. Therefore, new insights for the permeability properties of bedded coal and rock are summarized and proposed. (1) "Five guarantees" coring technology is worth for vigorous promotion and application. (2) The internal spatial fabric has the significant effect on the mechanical behavior evolution law of (bedded) coal and rock, but the effect is not dominant. (3) The permeability‐energy evolution models of (bedded) coal and rock should be constructed considering the idea of initial high in situ stress reduction, which is helpful for the energy visualization characterization of (bedded) coal and rock. Meanwhile, it can be combined with the structural evolution theory for in‐depth characterization and disclosure. (4) Researches on the permeability properties of (bedded) coal and rock under multi‐field or multi‐phase or phase‐field coupling conditions should be strengthened based on considering the initial damage produced and the distribution characteristics of in situ stress under the coring environment. (5) More accurate and scientific permeability evolution models of (bedded) coal and rock should be vigorously constructed based on the above insights.

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Experimental study on evolution in the characteristics of permeability, deformation, and energy of coal containing gas under triaxial cyclic loading‐unloading

Cited by 37 publications

References 16 publications

Energy Dissipation Characteristic of Red Sandstone in the Dynamic Brazilian Disc Test with SHPB Setup

Energy Dissipation Characteristic of Red Sandstone in the Dynamic Brazilian Disc Test with SHPB Setup

Experimental Study on the Evolution Trend of the Pore Structure and the Permeability of Coal under Cyclic Loading and Unloading

The permeability properties of bedded coal and rock: Review and new insights

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