Crack propagation law at the interface of FRP wrapped coal-backfilling composite structure. (15th August 2022)

• Record Type: Journal Article
• Authors: Shi, Xudong; Bai, Jinwen; Feng, Guorui; Wang, Kai; Cui, Boqiang; Guo, Jun; Yang, Xinyu; Song, Cheng
• Is Part Of: Construction & building materials. Volume 344(2022)
• Publication Date: 2022-08-15
• Subjects: Coal-backfilling composite structure -- Interface angle -- FRP -- Stress intensity factor -- Energy release rate; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.128229
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: FRP reinforcement technology was used to strengthen the interface stability of the coal-backfilling (CB) composite specimens. Crack propagation characteristics and failure modes of FRP wrapped CB composite specimens were obtained. The stress intensity factors and energy release rates at the interface centre of the composite specimens could quantitatively evaluated the effect of FRP wrapping on interfacial crack propagation. Abstract: The coal-backfilling (CB) composite structure jointly bears the excessive stress. The interface between the coal pillar and backfilling is the weakest area. The instability of the interface can induce the splitting failure of the composite structure, and fibre-reinforced polymer (FRP) could be applied to solve this problem. The Brazilian splitting laboratory tests were carried out on the CB composite specimens and FRP wrapped CB composite specimens (WCB) with different interface angles ( α = 0°, 15°, 30°, 45°, 60°, 75°, 90°). The failure modes of the above specimens were monitored by using the digital image correlation (DIC) technology. The stress intensity factors (SIFs) and the energy release rates (ERRs) at the interface centre of the composite specimens were calculated. The result shows that three types of failures, namely interfacial crack, tensile crack, and concentrated failure zone, appeared on the composite specimen. The interface angle was an important factor affecting the failure modes of the composite specimens. Interfacial stability of composite specimens could be enhanced by FRP wrapping. The SIFs KI and KII increased, and the expansion of the interface cracks was hindered by FRP wrapping. The critical load in the stable stage and the ERR of specimens were improved by FRP wrapping.