首页|Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling

Mechanical properties and damage characteristics of solidified body-coal combination in continuous driving and gangue backfilling

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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 min-ing.In this study,a mining technology of continuous driving and gangue backfilling(CDGB)was pro-posed.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 dam-age 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 evolu-tions 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,pro-viding certain reference for the study on the synergistic bearing of S-C combination during CDGB.

Continuous driving and gangue backfillingSolidified body-coal combinationMechanical propertiesDamage characteristicsDigital image correlation technologyAcoustic emission

Yi Tan、Hao Cheng、Wenbing Guo、Erhu Bai、Shaopu Zhang、Yu Wang、Zihao Li

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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,China

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaSupport Plan for Science & Technology Innovation Talents in Universities of Henan ProvinceScientific and technological innovation research team of Henan Polytechnic UniversityHenan Excellent Youth Science Foundation

U21A2010852322403521741085197410521HASTIT024T2021-5222300420045

2023

10.1016/j.ijmst.2023.08.003

矿业科学技术学报(英文版)
中国矿业大学

矿业科学技术学报(英文版)

CSTPCDCSCDEI
影响因子：1.222
ISSN：2095-2686
年,卷(期)：2023.33(10)
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