Acoustic emission responses and damage estimation of coal with carbon fiber-reinforced polymer confinement under uniaxial compression  

作　　者：Ze Xia Qiangling Yao Xuehua Li Linli Yu Yinghu Li Changhao Shan Lun Yan 

机构地区：[1]State Key Laboratory of Coal Resources and Safe Mining(CUMT),China University of Mining and Technology,Xuzhou,221116,China [2]School of Mines,China University of Mining and Technology,Xuzhou,221116,China [3]State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,221116,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第12期5077-5094,共18页岩石力学与岩土工程学报（英文）

基　　金：supported by Yunlong Lake Laboratory of Deep Underground Science and Engineering Project(Grant No.104024003);the Natural Science Foundation of the Jiangsu Provincial Basic Research Program(Grant No.BK20220024);the Open Sharing Fund for the large-scale instruments and equipment of the China University of Mining and Technology(Grant No.DYGX-2023-044).

摘　　要：Fiber-reinforced polymer(FRP)wrapping is a potential technique for coal pillar reinforcement.In this study,an acoustic emission(AE)technique was employed to monitor coal specimens with carbon FRP(CFRP)jackets during uniaxial compression,which addressed the inability to observe the cracks inside the FRP-reinforced coal pillars by conventional field inspection techniques.The spatiotemporal fractal evolution of the cumulated AE events during loading was investigated based on fractal theory.The results indicated that the AE response and fractal features of the coal specimens were closely related to their damage evolution,with CFRP exerting a significant influence.In particular,during the unstable crack development stage,the evolutionary patterns of the AE count and energy curves of the CFRPconfined specimens underwent a transformation from the slight shockemajor shock type to the slight shockesub-major shockeslight shockemajor shock type,in contrast to the unconfined coal specimens.The AE b-values decreased to a minimum and then increased marginally.The AE spatial fractal dimension increased rapidly,whereas the AE temporal fractal dimension fluctuated significantly during the accumulation and release of strain energy.Ultimately,based on the AE count and AE energy evolution,a damage factor was proposed for the coal samples with CFRP jackets.Furthermore,a damage constitutive model was established,considering the CFRP jacket and the compaction characteristics of the coal.This model provides an effective description of the stressestrain relationship of coal specimens with CFRP jackets.

关 键 词：Carbon fiber-reinforced polymer(CFRP)-confined coal Uniaxial compression Acoustic emission(AE) B-VALUE Fractal dimension 

分 类 号：TU45[建筑科学—岩土工程]