Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction
Abstract Broken coal and rock masses are the major part of the goaf. The compaction characteristics of coal and rock masses and the breakage law of whose particles during compaction exert an important influence on various aspects including control of strata motion, prediction of surface subsidence,...
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Online Access: | https://doi.org/10.1002/ese3.330 |
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doaj-c75fdf21e925483b8d229730fd5d76132020-11-24T21:28:52ZengWileyEnergy Science & Engineering2050-05052019-06-01731000101510.1002/ese3.330Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compactionBo Li0Yunpei Liang1Lei Zhang2Quanle Zou3State Key Laboratory of Coal Mine Disaster Dynamics and Control College of Resources and Environment Science Chongqing University Chongqing ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control College of Resources and Environment Science Chongqing University Chongqing ChinaSchool of Mines State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology Xuzhou ChinaState Key Laboratory of Coal Mine Disaster Dynamics and Control College of Resources and Environment Science Chongqing University Chongqing ChinaAbstract Broken coal and rock masses are the major part of the goaf. The compaction characteristics of coal and rock masses and the breakage law of whose particles during compaction exert an important influence on various aspects including control of strata motion, prediction of surface subsidence, and backfill mining. In this paper, the triaxial compaction experiment on broken coal‐rock masses with different mixing ratios was carried out. The test results showed that with the increase of stresses, the strain of coal‐rock masses gradually rose while the porosity, bulking factor, and degree of compaction gradually declined. During the compaction of coal‐rock masses, the fitting curves of the strain, porosity, bulking factor, and degree of compaction with stresses of coal samples all appeared as a cubic function of stresses. The breakage behavior of coal particles underwent three stages: structure re‐arrangement and breakage of particles, particle breakage, and compression‐induced deformation of particles. With increasing stress, the crushing amount of particles gradually grew while the increase rate of the crushed particles gradually decreased and the larger the particle strength was, the lower the increase rate of the crushing amount. Additionally, in the compaction process of samples, particle breakage mainly appeared before the stress reached to 8 MPa while the coal and rock particles were hardly crushed after the stress was larger than 8 MPa. With increasing stresses, the particle size gradation of samples gradually became reasonable and the lower the particle strength of samples was, the more reasonable the particle size gradation of compacted samples. The particle size gradation of various compacted and crushed samples showed a favorable fractal characteristic. In the stage with a low stress, the value of fractal dimension D rapidly grew and the fractal dimensions D of various samples tended to be stabilized after the stress reached to a high level.https://doi.org/10.1002/ese3.330broken coal‐rock massescompaction testfractal characteristicparticle breakageparticle size gradation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Bo Li Yunpei Liang Lei Zhang Quanle Zou |
spellingShingle |
Bo Li Yunpei Liang Lei Zhang Quanle Zou Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction Energy Science & Engineering broken coal‐rock masses compaction test fractal characteristic particle breakage particle size gradation |
author_facet |
Bo Li Yunpei Liang Lei Zhang Quanle Zou |
author_sort |
Bo Li |
title |
Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction |
title_short |
Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction |
title_full |
Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction |
title_fullStr |
Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction |
title_full_unstemmed |
Breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction |
title_sort |
breakage law and fractal characteristics of broken coal and rock masses with different mixing ratios during compaction |
publisher |
Wiley |
series |
Energy Science & Engineering |
issn |
2050-0505 |
publishDate |
2019-06-01 |
description |
Abstract Broken coal and rock masses are the major part of the goaf. The compaction characteristics of coal and rock masses and the breakage law of whose particles during compaction exert an important influence on various aspects including control of strata motion, prediction of surface subsidence, and backfill mining. In this paper, the triaxial compaction experiment on broken coal‐rock masses with different mixing ratios was carried out. The test results showed that with the increase of stresses, the strain of coal‐rock masses gradually rose while the porosity, bulking factor, and degree of compaction gradually declined. During the compaction of coal‐rock masses, the fitting curves of the strain, porosity, bulking factor, and degree of compaction with stresses of coal samples all appeared as a cubic function of stresses. The breakage behavior of coal particles underwent three stages: structure re‐arrangement and breakage of particles, particle breakage, and compression‐induced deformation of particles. With increasing stress, the crushing amount of particles gradually grew while the increase rate of the crushed particles gradually decreased and the larger the particle strength was, the lower the increase rate of the crushing amount. Additionally, in the compaction process of samples, particle breakage mainly appeared before the stress reached to 8 MPa while the coal and rock particles were hardly crushed after the stress was larger than 8 MPa. With increasing stresses, the particle size gradation of samples gradually became reasonable and the lower the particle strength of samples was, the more reasonable the particle size gradation of compacted samples. The particle size gradation of various compacted and crushed samples showed a favorable fractal characteristic. In the stage with a low stress, the value of fractal dimension D rapidly grew and the fractal dimensions D of various samples tended to be stabilized after the stress reached to a high level. |
topic |
broken coal‐rock masses compaction test fractal characteristic particle breakage particle size gradation |
url |
https://doi.org/10.1002/ese3.330 |
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