Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling
Recovery of the coal buried under buildings, railways and water bodies and the residual coal in irregularly arranged fully mechanized mining faces is a common engineering problem facing underground coal mining. In this study, a mining technology of continuous driving and gangue backfilling (CDGB) wa...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-10-01
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| Series: | International Journal of Mining Science and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2095268623001179 |
| _version_ | 1827728401271619584 |
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| author | Yi Tan Hao Cheng Wenbing Guo Erhu Bai Shaopu Zhang Yu Wang Zihao Li |
| author_facet | Yi Tan Hao Cheng Wenbing Guo Erhu Bai Shaopu Zhang Yu Wang Zihao Li |
| author_sort | Yi Tan |
| collection | DOAJ |
| description | Recovery of the coal buried under buildings, railways and water bodies and the residual coal in irregularly arranged fully mechanized mining faces is a common engineering problem facing underground coal mining. In this study, a mining technology of continuous driving and gangue backfilling (CDGB) was proposed. The technology, which can not only alleviate ground subsidence and gangue discharge, but also release the above-mentioned coals, contributes to green and efficient sustainable development of mining. The stability of the system of the solidified body-reserved coal pillar combination (S-C combination) is crucial to the CDGB technology. Therefore, it is of great significance to explore the mechanical and damage characteristics of S-C combination in the synergistic bearing process. First, four sets of different-shaped S-C combination specimens were fabricated and a S-C combination bearing structure in CDGB was constructed to explore the differences in mechanical characteristics and damage modes of different-shaped S-C combination specimens during CDGB. Subsequently, their surface strain field evolutions and acoustic emission (AE) response characteristics in the load-bearing process were obtained with the aid of the digital image correlation technique and the AE signal monitoring system. Furthermore, a damage evolution model based on AE parameters and mechanical parameters was established to clarify the damage evolution law. The following results were obtained: (1) The free area of S-C combination can serve as a quantitative index to evaluate the stability of the overburden control system; (2) The concept of critical value k of the free area was first proposed. When the free area exceeds the critical value k (free area ratio greater than 1.13), the deformation resistance and the free area changes becomes negatively correlated; (3) As the free area expands, the failure of the S-C combination specimen evolves from tensile failure to shear failure. The distribution characteristics of the axial strain field also verified such a change in the failure mode; (4) When the free area expands, the peak AE count gradually changes from “double peaks” to “a single peak”. In this process, the expansion of free area shortens the time for accumulating and releasing energy during loading. Micro cracks generated in the specimen change from a phased steep growth to a continuous increase, and the process in which micro cracks develop, converge, intersect and connect to form macro cracks accelerates. The damage evolution law concluded based on AE parameters and mechanical parameters can well characterize the damage evolution process of S-C combination, providing certain reference for the study on the synergistic bearing of S-C combination during CDGB. |
| first_indexed | 2024-03-10T23:29:41Z |
| format | Article |
| id | doaj.art-627e45b5c51b4737914e8e677ee3ca01 |
| institution | Directory Open Access Journal |
| issn | 2095-2686 |
| language | English |
| last_indexed | 2024-03-10T23:29:41Z |
| publishDate | 2023-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | International Journal of Mining Science and Technology |
| spelling | doaj.art-627e45b5c51b4737914e8e677ee3ca012023-11-19T04:34:35ZengElsevierInternational Journal of Mining Science and Technology2095-26862023-10-01331012171228Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfillingYi Tan0Hao Cheng1Wenbing Guo2Erhu Bai3Shaopu Zhang4Yu Wang5Zihao Li6School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454000, ChinaSchool of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; Corresponding author.School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454000, ChinaSchool of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization, Henan Polytechnic University, Jiaozuo 454000, ChinaSchool of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, ChinaSchool of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, ChinaSchool of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, ChinaRecovery of the coal buried under buildings, railways and water bodies and the residual coal in irregularly arranged fully mechanized mining faces is a common engineering problem facing underground coal mining. In this study, a mining technology of continuous driving and gangue backfilling (CDGB) was proposed. The technology, which can not only alleviate ground subsidence and gangue discharge, but also release the above-mentioned coals, contributes to green and efficient sustainable development of mining. The stability of the system of the solidified body-reserved coal pillar combination (S-C combination) is crucial to the CDGB technology. Therefore, it is of great significance to explore the mechanical and damage characteristics of S-C combination in the synergistic bearing process. First, four sets of different-shaped S-C combination specimens were fabricated and a S-C combination bearing structure in CDGB was constructed to explore the differences in mechanical characteristics and damage modes of different-shaped S-C combination specimens during CDGB. Subsequently, their surface strain field evolutions and acoustic emission (AE) response characteristics in the load-bearing process were obtained with the aid of the digital image correlation technique and the AE signal monitoring system. Furthermore, a damage evolution model based on AE parameters and mechanical parameters was established to clarify the damage evolution law. The following results were obtained: (1) The free area of S-C combination can serve as a quantitative index to evaluate the stability of the overburden control system; (2) The concept of critical value k of the free area was first proposed. When the free area exceeds the critical value k (free area ratio greater than 1.13), the deformation resistance and the free area changes becomes negatively correlated; (3) As the free area expands, the failure of the S-C combination specimen evolves from tensile failure to shear failure. The distribution characteristics of the axial strain field also verified such a change in the failure mode; (4) When the free area expands, the peak AE count gradually changes from “double peaks” to “a single peak”. In this process, the expansion of free area shortens the time for accumulating and releasing energy during loading. Micro cracks generated in the specimen change from a phased steep growth to a continuous increase, and the process in which micro cracks develop, converge, intersect and connect to form macro cracks accelerates. The damage evolution law concluded based on AE parameters and mechanical parameters can well characterize the damage evolution process of S-C combination, providing certain reference for the study on the synergistic bearing of S-C combination during CDGB.http://www.sciencedirect.com/science/article/pii/S2095268623001179Continuous driving and gangue backfillingSolidified body-coal combinationMechanical propertiesDamage characteristicsDigital image correlation technologyAcoustic emission |
| spellingShingle | Yi Tan Hao Cheng Wenbing Guo Erhu Bai Shaopu Zhang Yu Wang Zihao Li Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling International Journal of Mining Science and Technology Continuous driving and gangue backfilling Solidified body-coal combination Mechanical properties Damage characteristics Digital image correlation technology Acoustic emission |
| title | Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling |
| title_full | Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling |
| title_fullStr | Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling |
| title_full_unstemmed | Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling |
| title_short | Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling |
| title_sort | mechanical properties and damage characteristics of solidified body coal combination in continuous driving and gangue backfilling |
| topic | Continuous driving and gangue backfilling Solidified body-coal combination Mechanical properties Damage characteristics Digital image correlation technology Acoustic emission |
| url | http://www.sciencedirect.com/science/article/pii/S2095268623001179 |
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