Experimental study on permeability of crushed gangues during compaction

Kong, Heng; Chen, Zhanqing; Wang, Luzhen; Hai-de, Shen

doi:10.1016/j.minpro.2013.04.012

Cited by 31 publications

(25 citation statements)

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“…Miao et al (2011) further studied the seepage properties of broken sandstone with five grain sizes and different porosities by means of an electro-hydraulic servo-controlled test system (MTS815) and a patented seepage device. Kong et al (2013) tested the permeability of crushed gangues with six different particle sizes during compaction on the CMT5305 electronic universal testing machine and analysed the relationships of seepage velocity, permeability, and non-Darcy β factor to the porosity, particle size, and diameter distribution. Using the apparatus and MTS system, Ma et al (2014) tested crushed mudstone, limestone, and sandstone specimens and obtained the relationship between permeability and variable grain diameter of (2.5-5 mm), (5-10 mm), (10-15 mm), (15-20 mm), and (mixed sizes) under variable axial displacement (10, 15, 20, 25, 30, 35, and 40 mm).…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the seepage property of saturated broken red sandstone of continuous gradation

et al. 2017

Bull Eng Geol Environ

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The statues of seepage in broken red sandstone may become unsteady due to the effects of water erosion, so it is important to consider the effect of mass loss on the permeability of broken red sandstone. In this study, the seepage property and water outburst were measured through a self-made variable mass seepage experimental system. In the test, the particles of broken red sandstone satisfied the Talbol grading theory. The influences of Talbol index n on the hydraulic, mass loss of particles, porosity and permeability were investigated. The experimental results show that the seepage process in the broken red sandstone usually experiences three stages: the initial stage, mutation stage and stabilization stage. Broken specimens can bear water erosion at the initial stage. However, the internal structure of specimens produces instability because the seepage of small particles gradually increases in the mutation stage. Finally, stable underground watercourses of the specimen were formed at the stabilization stage. It is also found that the mass loss, the peak of mass loss rate, the final porosity after seepage, the permeability at the mutation and stable stages were negatively related to the Talbol index n of the specimen. The seepage mutation occurred sooner for smaller n. The permeabilities of specimens with different Talbol indices differed by more than 10 times after seepage mutation.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation on the seepage property of saturated broken red sandstone of continuous gradation

et al. 2017

Bull Eng Geol Environ

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“…It is observed that there is a sudden gas pressure increase in stage 1 both for Type I and Type II due to the sudden supply of gas pressure. This up‐rush occurs in a short period of time and disappears rapidly owing to a rather large, effective seepage throat for crushed samples . Subsequently, the mutation stage appears.…”

Section: Resultsmentioning

confidence: 99%

“…These studies indicate that the pore pressure gradient and flow velocity can be fitted by the Forchheimer equation . Moreover, the water‐flow properties of crushed rocks are strongly influenced by axial displacement, grain diameter size, and the type of stones . Recently, increasing attention has been paid to gas‐flow characterization of crushed coal under constant axial load.…”

Section: Introductionmentioning

confidence: 98%

“…Legrand 26 tested the flow pressure drop through crushed rocks and reanalyzed the flow behaviors with the capillary model in comparison with a model that used the square root of permeability as characteristic length. Miao et al 16,[27][28][29] designed a water-flow apparatus for crushed rocks and performed steady-state tests to reveal the seepage properties of different rocks including crushed sandstone, limestone, mudstone, and coal gangue. These studies indicate that the pore pressure gradient and flow velocity can be fitted by the Forchheimer equation.…”

Section: Introductionmentioning

confidence: 99%

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The correlation between crushed coal porosity and permeability under various methane pressure gradients: a case study using Jincheng anthracite

Feng

Jiang

et al. 2018

Greenhouse Gases

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As a greenhouse gas (GHG), methane (CH4) emitted from underground mines contributes 17% to total anthropogenic greenhouse gas emissions. Gas drainage is the main measure to resolve this problem, and knowledge of methane flow in surrounding coal and rocks greatly influences our thinking and handling strategies for reducing CH4 emissions. However, due to the lack of matched testing systems, current studies are generally confined to considering methane flow properties in porous and fractured coal and rocks, whereas methane flow behaviors in crushed coal have not been extensively studied and understood yet. In this study, the relationships between crushed coal porosity and permeability under various methane pressures are investigated using a self‐designed gas permeation testing system, and continuous measurements of methane pressure and flow rate have been conducted. The results show that the permeability properties of crushed coal are closely related to the coal porosity, methane pressure, and axial stress. Darcy flow transfers to slip flow in crushed coal in the latter stage of coal‐mine methane drainage in crushed coal, and the permeability of crushed coal has a magnitude of 10−12–10−11 m2, which is rather larger than that of porous and fractured coals. The pseudo‐threshold pressure gradient (TPG) decreases with the growth of porosity, and it is rather smaller than that of lower permeability reservoirs (LPR). With an increase in methane pressure, the permeability of crushed coal presents a logarithmic growth trend; by contrast, it displays an exponential growth trend with an increase in porosity. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

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“…Meanwhile, the addition of CG increased the dispersion by 130–760% and decreased the Peclet number and mobile water fraction by 55–87% and 12–31%, respectively (Zhou et al, ). Kong, Chen, Wang, and Shen () also found that the permeability of crushed gangue of the same size decreases with increasing their size, in the range of 10 −15 –10 − 12 m 2 ; moreover, the permeability of the mixed gangues is the largest during compaction. In comparison, FA is composed primarily of mostly silt‐sized particles with low bulk density, and its addition to soils of coarse texture may permanently change the soil texture, resulting in increased micro porosity and water‐retention capacity (Ghodrati, Sims, & Vasilas, ; Ram & Masto, ).…”

Section: Introductionmentioning

confidence: 91%

The effects of coal gangue and fly ash on the hydraulic properties and water content distribution in reconstructed soil profiles of coal‐mined land with a high groundwater table

Wang

Bai

et al. 2016

Hydrological Processes

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Soil water systems have been severely degraded in coal‐mined and subsiding land, where a shallow groundwater table is also present. The present paper discussed the effects of fly ash (FA) and coal gangue (CG) as filling materials on the hydraulic properties and water content distribution in a profile for the purpose of rehabilitating subsided lands. The saturated water content, water characteristic curve, and water diffusivity of local soil, FA, CG, and a mixture of FA and CG (“mixed filling”) were characterized. A column experiment was conducted to investigate the changes of water content in profiles reconstructed from the combination of soil and filling materials, including soil only, FA, CG, and a mixture of FA and CG, which were used to fill the lower part of the reconstructed profile. The mixture of FA and CG was found to possess similar hydraulic properties to those of the soil, particularly high water‐holding capacity and permeability. Moreover, the volumetric water contents in the whole profile containing the mixture of FA and CG were consistent with those of the profile reconstructed with soil only. As a result, it is recommended to adopt the mixture of FA and CG for reconstructing the lower profile of the land to alleviate or rehabilitate subsided land in coal mines.

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Experimental study on permeability of crushed gangues during compaction

Cited by 31 publications

References 1 publication

Experimental investigation on the seepage property of saturated broken red sandstone of continuous gradation

Experimental investigation on the seepage property of saturated broken red sandstone of continuous gradation

The correlation between crushed coal porosity and permeability under various methane pressure gradients: a case study using Jincheng anthracite

The effects of coal gangue and fly ash on the hydraulic properties and water content distribution in reconstructed soil profiles of coal‐mined land with a high groundwater table

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