Rarefaction shock waves, outbursts and consequential coal damage

Litwiniszyn, J.

doi:10.1016/0148-9062(90)91004-q

Cited by 7 publications

(6 citation statements)

References 7 publications

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“…Litwiniszyn (1990) has used a high-speed camera to study coal fracturing and has observed the formation of subparallel cracks similar to those observed in our experiments. The theoretical analysis of the rockburst phenomena also indicated the important role of unloading and fragmentation waves (Khristianovich 1979;Kovalenko 1980).…”

Section: Fragmentation Mechanismssupporting

confidence: 71%

“…Several experimental studies have been conducted on coal fracturing by rapid decompression (Kravchenko 1955;Borisenko 1985;Litwiniszyn 1990Litwiniszyn , 1991. Litwiniszyn (1990) has used a high-speed camera to study coal fracturing and has observed the formation of subparallel cracks similar to those observed in our experiments.…”

Section: Fragmentation Mechanismssupporting

confidence: 62%

“…Experiments performed on gray dacite of the 18 May 1980 Mount St. Helens eruption, at temperatures up to 915 7C and a pressure differential of ;12 MPa, resulted in fragmentation of the dacite. The results of those experiments have demonstrated that the rapid decompression of a viscous vesicular dacite (h610 10.8 Pa s) can generate pyroclasts having angular shapes explained by the brittle fragmentation of viscous magma undergoing high-tensile strains (Dingwell and Webb 1989;1990;Dingwell 1995;Webb and Dingwell 1990). BrittIe disruption of dacite was observed over the entire experimental temperature range (15-915 7C), implying that the behaviour of highly viscous magma is similar to that of porous solid material undergoing rapid decompression (Alidibirov and Dingwell 1996a).…”

Section: Introductionmentioning

confidence: 89%

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Magma fragmentation dynamics: experiments with analogue porous low-strength material

Alidibirov

Panov

1998

Bulletin of Volcanology

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Experiments were conducted on the fragmentation of analogue low-strength porous material (plastiprin) by rapid decompression in a shock-tubetype apparatus. The porous samples (lengthp365 mm, cross-section dimensions 40!40 mm) pressurized by air to pressures up to 0.9 MPa, were rapidly decompressed to 0.1 MPa. Rapid decompression of samples caused fragmentation and ejection of the fragmentation products into a large volume tank. The process of analogue material fragmentation was documented using highspeed cinematography and dynamic pressure measurements. The duration of the fragmentation event is significantly shorter than that of the ejection event. The fragmentation of material precedes the acceleration of fragments. As a result of fragmentation, sub-parallel fractures are generated. The characteristic fragment size decreases as the initial pressure differential increases. The ejected fragments obtain velocities of 60 m/s. The mechanisms of material fragmentation during unloading and fragmentation wave propagation are discussed. The experimental results provide insight into the fragmentation dynamics of highly viscous magmas in which brittle failure at high strain rate is possible.

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Section: Fragmentation Mechanismssupporting

confidence: 71%

Section: Fragmentation Mechanismssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 89%

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Magma fragmentation dynamics: experiments with analogue porous low-strength material

Alidibirov

Panov

1998

Bulletin of Volcanology

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“…They generate a new simple rarefaction shock wave Litwiniszyn (1990) like that which caused the formation and the throwing-away of the first slice. This wave causes the loosening and the throwing-away of another slice.…”

Section: Laboratory Investigationsmentioning

confidence: 98%

Rarefaction shock waves in porous media that accumulate CO2, CH4, N2

Litwiniszyn

1994

Shock Waves

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Abstract. In this paper, a porous medium whose core is built from a solid substance is considered. Such a medium can accumulate liquid and gaseous substances absorbing on the surface of the solid body and diffusing within its molecular lattice. The medium forms a so-called solid solution. A change in the values of the thermodynamic parameters of this; medium leads to phase transitions in these substances. Besides, some other associated phenomena may occur. There are given the results of laboratory analyses concerning the relation between the specific volume V of the solid solution formed by the coal with CO2, CH4, N2 dissolved in it and its corfining pressure p. This relation indicates the possibility of the propagation of a rarefaction shock waves in such a medium.A mathematical model of the generation of such waves and its specific applications to describe the initial boundary conditions affected during the experiments presented. The results of these experiments have confirmed the adopted model, particularly those aspects that are concerned with the specific sliced structures of the coal medium with the accumulated CO2 and N2, through which a rarefaction shock wave has passed (Figs. 10a, 10b, lla, and llb). The presented model explains the phenomena of sudden massive rock-and-gas outbursts, occurring in nature, e.g. as a result of disturbing the primary equilibrium of the rocks in the Earth crust which form a solid solution, by underground mining exploitation.

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“…The mining disturbance is an important factor that induces rockburst in roadways (Li et al, 2020;Ye et al, 2022). Litwiniszyn (2009) regarded rockburst as a result of an impact wave released by gravity-induced fractures of strata overlying a chamber. Li et al studied the mechanical properties of hard rocks under dynamicstatic loading by carrying out laboratory dynamic-static loading tests and simulated the rockburst induction mechanism by dynamic disturbances under high stress (Lei et al, 2005;Li et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

Xuan,

Cheng,

et al. 2023

Front. Energy Res.

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Influenced by the deep high-stress environment, geological structures, and mining disturbance in coal mines, the frequency of rockburst disasters in roadways is increasing. This research analyzed energy evolution characteristics during rockburst development in the elastic bearing zone and energy conversion in the plastic failure zone. The critical energy criteria for structural instability of roadway surrounding rocks were deduced. Numerical software was also applied to simulate the energy evolution during rockburst development in surrounding rocks of rockburst-prone roadways under conditions of different mining depths and coal pillar widths. The occurrence mechanism of rockburst deep in coal mines was analyzed from the perspective of energy in structures of deep roadway surrounding rock in coal mines. The research results show that the critical energy criteria are closely related to the elastic strain energy stored in deep roadway surrounding rocks and the energy absorbed by support systems. The impact energy in roadways is directly proportional to the square of the stress concentration factor k. Moreover, as the mining depth increases, the location of the peak point of maximum energy density gradually shifts to coal ahead of the working face. The larger the mining depth is, the more significantly the energy density is influenced by advanced abutment pressure of the working face and the wider the affected area is. With the increment of the coal pillar width, the distance from the peak point of energy density to the roadway boundary enlarges abruptly at first and then slowly, and the critical coal pillar width for gentle change in the distance is 30 m. Changes in the peak elastic energy density in coal pillars with the coal pillar width can be divided into four stages: the slow increase stage, abrupt increase stage, abrupt decrease stage, and slow decrease stage. The elastic energy density is distributed asymmetrically in deep roadway surrounding rocks in coal mines. Under the action of structures of roadway surrounding rocks, energy evolution in these structures differs greatly during rockburst development under conditions of different coal pillar widths. This research provides an important theoretical basis for the support of rockburst-prone roadways during deep coal mining.

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Rarefaction shock waves, outbursts and consequential coal damage

Cited by 7 publications

References 7 publications

Magma fragmentation dynamics: experiments with analogue porous low-strength material

Magma fragmentation dynamics: experiments with analogue porous low-strength material

Rarefaction shock waves in porous media that accumulate CO2, CH4, N2

Energy evolution mechanism during rockburst development in structures of surrounding rocks of deep rockburst-prone roadways in coal mines

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