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

Chen, Shaojie; Jiang, Tianqi; Wang, Huaiyuan; Fan, Feng; Yin, Dawei; Xiushan, Li

doi:10.1002/ese3.476

Cited by 34 publications

(16 citation statements)

References 67 publications

(85 reference statements)

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“…The strength properties of rocks would be significantly deteriorated after the cyclic dry-wet treatment. Khanlari et al [22], Özbek [21], Zhao et al [32], Huang et al [40], and Chen et al [41] performed static compression tests after dry and wet cycles on sandstone, melted limestone, mudstone, and coalstone, respectively. All of the results shown that with the increase of the number of dry and wet cycles, the uniaxial compressive strength and triaxial compressive strength of the rock sample decreased to varying degrees.…”

Section: Geofluidsmentioning

confidence: 99%

Deterioration of Physical and Mechanical Properties of Rocks by Cyclic Drying and Wetting

et al. 2021

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Both surface and underground rocks in nature often undergo repeated drying and wetting. The dry-wet cycle is a weathering effect that includes physical and chemical processes, which has varying degrees of degradation effects on the physical and mechanical properties of rocks. This paper analyzes and discusses this kind of rock degradation based on the existing literature data. First, the deterioration degree of various physical and mechanical properties (including density, P-wave velocity, porosity, static and dynamic compressive/tensile strength, and fracture toughness) is summarized as the number of dry-wet cycles increases. Secondly, the possible degradation mechanism of the dry-wet cycle is explained in terms of clay mineral swelling, solute migration, and microcrack evolution. Then, the damage constitutive model of the rock after cyclic dry-wet treatment is introduced. Finally, the issues that need to be studied in the future are put forward.

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Section: Geofluidsmentioning

confidence: 99%

Deterioration of Physical and Mechanical Properties of Rocks by Cyclic Drying and Wetting

et al. 2021

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“…Talapatra et al (2020) revealed the evolution law of coal deformation and strain and described the influence of moisture content on the permeability of coal through porous media in wet reservoir [26]. studied the influence of water-coal interaction on the mechanical strength of coal [27]. The results showed that with the increase of continuous wetting time and the number of dry and wet cycles, the peak stress and elastic modulus decreased and the peak strain increased.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Mechanical Properties of Briquette Coal Samples with Different Moisture Content

et al. 2021

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Coal seam water injection is an important technical method to prevent and control coal and gas outburst and other disasters. Water can soften coal and change its mechanical properties. In order to study the mechanical properties of coal samples with different moisture content, briquette coal samples with five moistures content (4%, 6%, 8%, 10%, and 12%) were selected to carry out triaxial compression tests under different confining pressures (0.1, 0.2, 0.4, 0.8, and 1.2 MPa). Then, the mechanical response mechanism of the water-bearing briquette coal was analyzed. The results show that the slope of the linear elastic stage of the stress-strain curve gradually decreases with the increase of moisture content. Water-bearing coal exhibits strain strengthening characteristics under high confining pressure, which transforms the water-bearing coal from brittle to ductile state. The peak stress under different moisture content conditions shows a linear relationship with the confining pressure. The internal friction angle decreases linearly with the increase of moisture content. The cohesion varies parabolically with the increase of moisture content and reaches the maximum value when the moisture content is 8%. The coal body with moisture content between 7% and 9% has a high bonding force, which is beneficial to the consolidation of the coal body. Therefore, ensuring a reasonable moisture content of coal through coal seam injection can provide a basis for preventing coal and gas outburst.

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“…e subsurface works in the western part of China is not only affected by the low temperature environment and freezethaw cycles but also influenced by factors such as acid rain and groundwater erosion. Not only hydrochemical reaction causes elements to redistribute between rocks and water [1], the volume expansion of water in the pores will also produce freezing force during the freeze-thaw cycles [2,3]. e freezing force leads to the expansion of the original defect and the generation and expansion of new cracks, which cause imbalances within its soil particles, water molecules, and ions and decrease in strength and increase in compressibility.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Mechanical Properties of Sandstone under the Action of Chemical Erosion and Freeze‐Thaw Cycles

Cui

Qin

Wang

et al. 2021

Advances in Civil Engineering

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In order to study the mechanical properties of sandstone under the coupling action of chemical erosion and freeze-thaw cycles, the fine-grained yellow sandstone in a mining area in Zigong, China, is collected as the research object. The changes in mechanical properties of yellow sandstone under the coupling action of chemical solution erosion and freeze-thaw cycles are analyzed based on uniaxial compression tests (UCTs) and triaxial compression tests (TCTs). The results show that, with the increase in freeze-thaw cycles, the compressive strength, elastic modulus, and cohesion of the sandstone samples decrease with varying degrees. Under constant freeze-thaw cycles, the most serious mechanical properties of degradation are observed in acidic solution, followed by alkaline solution and neutral solution. Under different confining pressures, the compressive strength and elastic modulus of the sandstone samples decrease exponentially with the increase in freeze-thaw cycles. Under the action of the chemical solution erosion and freeze-thaw cycles, the internal friction angle fluctuates around 30°. For the cohesion degradation, 35.4%, 29.3%, and 27.2% degradation are observed under acidic, alkaline, and neutral solutions. Nuclear magnetic resonance imaging shows that the chemical erosion and freeze-thaw cycles both promote the degradation of rock properties from surface to interior; after 45 freeze-thaw cycles, the mechanical properties drop sharply. To properly design rock tunneling support and long-term protection in the cold region, the impact of both freeze-thaw cycles and chemical erosion should be considered.

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

Cited by 34 publications

References 67 publications

Deterioration of Physical and Mechanical Properties of Rocks by Cyclic Drying and Wetting

Deterioration of Physical and Mechanical Properties of Rocks by Cyclic Drying and Wetting

Experimental Study on Mechanical Properties of Briquette Coal Samples with Different Moisture Content

Experimental Study on the Mechanical Properties of Sandstone under the Action of Chemical Erosion and Freeze‐Thaw Cycles

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