Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions
Underground coal mines are frequently subjected to water infusion, resulting in many mining hazards. This study investigated the effect of water infusion on the stress and energy evolution characteristics of coal specimens representing isolated pillars under different initial axial stress conditions...
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doaj-de9ebdfb30034608b704b1d2665596ff2020-11-25T01:37:45ZengMDPI AGApplied Sciences2076-34172020-03-01106204310.3390/app10062043app10062043Water Infusion on the Stability of Coal Specimen under Different Static Stress ConditionsZilong Zhou0Lihai Tan1Xin Cai2School of Resources & Safety Engineering, Central South University, Changsha 410010, ChinaSchool of Resources & Safety Engineering, Central South University, Changsha 410010, ChinaSchool of Resources & Safety Engineering, Central South University, Changsha 410010, ChinaUnderground coal mines are frequently subjected to water infusion, resulting in many mining hazards. This study investigated the effect of water infusion on the stress and energy evolution characteristics of coal specimens representing isolated pillars under different initial axial stress conditions using the discrete element method. A water infusion distribution model was developed, in which random functions were employed to describe water distribution for the purpose of realizing the dispersion of results for a better reliability. Based on the results, a stress-level classification was presented to evaluate the water effect on pillars’ instability. For the investigated coal specimens, the water weakening effect on stress and energy remains stable when the axial geo-stress on pillars is less than 65% of uniaxial compressive strength (UCS). In contrast, when the axial stress coefficient is greater than 65%, pillars become unstable eventually. A higher axial stress coefficient is more likely to introduce a lower critical instability point of the water saturation coefficient for pillars in the process of water infusion. However, the instability point remains random to some extent for specimens following the same water distribution rule under the identical test condition. Two instability types, which also happened randomly, were observed in the numerical results for damaged coal specimens under different water saturation coefficients and axial geo-stresses, namely free-falling and step-falling.https://www.mdpi.com/2076-3417/10/6/2043water infusioncoal pillarinstability processenergy characteristicdiscrete element method |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Zilong Zhou Lihai Tan Xin Cai |
spellingShingle |
Zilong Zhou Lihai Tan Xin Cai Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions Applied Sciences water infusion coal pillar instability process energy characteristic discrete element method |
author_facet |
Zilong Zhou Lihai Tan Xin Cai |
author_sort |
Zilong Zhou |
title |
Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions |
title_short |
Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions |
title_full |
Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions |
title_fullStr |
Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions |
title_full_unstemmed |
Water Infusion on the Stability of Coal Specimen under Different Static Stress Conditions |
title_sort |
water infusion on the stability of coal specimen under different static stress conditions |
publisher |
MDPI AG |
series |
Applied Sciences |
issn |
2076-3417 |
publishDate |
2020-03-01 |
description |
Underground coal mines are frequently subjected to water infusion, resulting in many mining hazards. This study investigated the effect of water infusion on the stress and energy evolution characteristics of coal specimens representing isolated pillars under different initial axial stress conditions using the discrete element method. A water infusion distribution model was developed, in which random functions were employed to describe water distribution for the purpose of realizing the dispersion of results for a better reliability. Based on the results, a stress-level classification was presented to evaluate the water effect on pillars’ instability. For the investigated coal specimens, the water weakening effect on stress and energy remains stable when the axial geo-stress on pillars is less than 65% of uniaxial compressive strength (UCS). In contrast, when the axial stress coefficient is greater than 65%, pillars become unstable eventually. A higher axial stress coefficient is more likely to introduce a lower critical instability point of the water saturation coefficient for pillars in the process of water infusion. However, the instability point remains random to some extent for specimens following the same water distribution rule under the identical test condition. Two instability types, which also happened randomly, were observed in the numerical results for damaged coal specimens under different water saturation coefficients and axial geo-stresses, namely free-falling and step-falling. |
topic |
water infusion coal pillar instability process energy characteristic discrete element method |
url |
https://www.mdpi.com/2076-3417/10/6/2043 |
work_keys_str_mv |
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1725057685658796032 |