To reveal the strengthening effect of the CFRP method on the fire-damaged segment. In this study, the fire-damaged segment was strengthened with the CFRP-PCM method and CFRP-sheet method, respectively. The crack development, deformation characteristics, failure mode, load-bearing behaviour and internal force evolution of the segment specimens were analysed. The results indicated that the CFRP-PCM method can improve the crack development of the segment, while the CFRP-sheet method can only prevent the crack initiation of the segment before tearing between the CFRP sheet and the segment. The fire-damaged segment strengthened by the CFRP-PCM method exhibited gradual deformation and failure characteristics, whereas the fire-damaged segment strengthened by the CFRP-sheet method exhibited sudden failure with no discernible damage characteristics. The CFRP-sheet method had a higher initial strengthening effect on the fire-damaged segment than the CFRP-PCM method before tearing between the CFRP sheet and the segment, while the strength utilisation rate of the CFRP grid was higher than that of the CFRP sheet. The CFRP method of strengthening the fire-damaged segment can improve the tensile strength of the tension zone, increase the sectional stiffness, and restore the load-bearing capacity; however, this comes at the expense of the deformation capacity. The study provides a reference value for the strengthening design of fire-damaged linings in shield tunnels.

中文翻译：

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CFRP方法对火灾受损管段的加固效果


揭示CFRP方法对火灾受损管段的加固效果。在本研究中，分别采用 CFRP-PCM 方法和 CFRP-片材方法对火灾损坏部分进行加固。分析了管片试件的裂纹发展、变形特征、破坏模式、承载行为和内力演化。结果表明，CFRP-PCM方法可以改善管片裂纹的发展，而CFRP-片材方法只能在CFRP片材和管片之间撕裂之前阻止管片裂纹的萌生。采用CFRP-PCM方法加固的火灾损坏段表现出逐渐变形和破坏特征，而采用CFRP-片材方法加固的火灾损坏段表现出突然破坏，没有明显的损坏特征。在CFRP片材与管片之间撕裂前，CFRP-片材法对火灾受损管片的初始强化效果高于CFRP-PCM法，且CFRP网格的强度利用率高于CFRP片材。采用碳纤维布加固火灾受损管段的方法，可以提高受拉区的抗拉强度，增加截面刚度，恢复承载能力；然而，这是以牺牲变形能力为代价的。研究结果为盾构隧道火损衬砌加固设计提供参考价值。