Research on the mechanical reinforcement and fracture sensing of coal samples constrained by carbon fiber composite mortar
NING Shan
ZHU Weibing
XU Jialin
LI Zhu
ZHAO Bozhi
Abstract：To address the prevention and control needs for dynamic disasters easily induced by insta-bility of underground coal pillars,a constraint-enhancement and damage-monitoring method based on carbon-fiber composite mortar was developed.A systematic study was conducted by integrating theoretical analysis,COMSOL electric-field simulations,resistance monitoring,and uniaxial com-pression tests to thoroughly examine the mechanical strength,resistance change rate,and damage characteristics of coal specimens confined with composite mortars at different carbon-fiber contents.The results show that carbon fibers form a continuous network structure within the mortar matrix,enhancing the mechanical strength and electrical conductivity of the composite mortar,suppressing the migration of soluble charged ions,and shifting the conduction mechanism from ionic to elec-tronic conduction,thereby significantly reducing noise interference during resistance monitoring.At a carbon-fiber content of 2.0%,the composite mortar's resistivity is reduced by four orders of magnitude compared with plain cement mortar,the peak-to-peak noise in resistivity monitoring is reduced by five orders of magnitude relative to plain mortar specimens,and the compressive/tensile strengths increase by 136.6%and 135.1%,respectively.Wrapping coal specimens with carbon-fiber composite mortar applies circumferential confinement and enhances their mechanical strength;meanwhile,the composite mortar establishes preferential conductive pathways on the coal surface,making it more sensitive to crack propagation.With 2.0%carbon fiber content,the uniaxial com-pressive strength of the confined coal specimen increases by 25.0%compared with plain coal,and the stress sensitivity is 1.94 times that of coal specimens confined with plain mortar.When composite-mortar-confined coal specimens fracture,the stress-strain response and resistance change rate drop synchronously,enabling accurate identification of fracture events by capturing abrupt resis-tance signals.Using carbon-fiber composite mortar to confine coal specimens achieves simultane-ous mechanical reinforcement and real-time,non-destructive monitoring of the fracture process.These findings expand the application scope of carbon-fiber composite materials in mining and pro-vide a new technical pathway for damage monitoring of underground coal bodies.
Keywords：carbon fiber composite mortardamage monitoringcoal pillar reinforcementme-chanical enhancementresistance change rate
Publication Date：2026-03-31
Online Publishing Date：2026-04-08(First online date of this platform, not the publication date of the document)
Pages：15( 484-498 )