CFRP网格-喷射ECC复合增强隧道管片受力性能研究

Mechanical behavior of tunnel segment strengthening with CFRP grid reinforced sprayed ECC composite

为提升隧道管片承载力和耐久性,提出一种具备耐腐蚀、施工方便的结构增强方式。在对喷射ECC工作性能和受力性能进行优化的基础上,采用CFRP网格与喷射ECC(CFRP-ECC)复合增强盾构隧道管片。考虑增强材料、ECC层厚度以及CFRP网格等参数,对两端简支的CFRP-ECC复合增强盾构隧道管片进行静力加载试验,研究其受弯性能。结果表明:经过ECC和CFRP-ECC复合增强后的管片,其开裂弯矩较未增强管片分别增加了26.7%和13.3%,有效抑制了裂缝的产生;喷射厚20 mm ECC管片的承载力和延性均得到提升,其位移延性系数相较于未增强管片提高了44.6%;仅粘贴CFRP布增强管片的承载力与未增强管片的基本相同,但位移延性系数提高了195%。此外,基于ABAQUS建立的有限元分析模型能有效分析管片及CFRP-ECC增强管片的受力性能和破坏形态。通过黏结应力-滑移模型建立的ECC与混凝土间的接触能有效模拟界面的黏结性能。

To enhance the loadbearing capacity and durability of tunnel segments,a structural reinforcement method that is corrosionresistant and easy to construct was proposed.Based on optimizing the working performance and mechanical properties of sprayed ECC,CFRP grid-reinforced sprayed ECC(CFRP-ECC)composite was used to strengthen the tunnel segment in this paper.Considering parameters such as reinforcing materials,thickness of ECC and CFRP grid,static loading tests were conducted on the simply supported CFRP-ECC composite reinforced tunnel segments to investigate their mechanical behavior.The test results indicate that the cracking bending moment of segment strengthening with ECC and CFRP-ECC increased by 26.67%and 13.33%,respectively,compared with the unreinforced segment.The proposed strategy effectively inhibits the generation of cracks.Both the ultimate bearing capacity and ductility of the segment are improved by strengthening with 20 mm thickness of ECC,whose ductility increased by 44.6%compare to unreinforced segment.The ultimate bearing capacity of the segment reinforced with CFRP fabric is slightly lower than that of the unreinforced segment,but its ductility is increased by 195%.In addition,the analytical model established by ABAQUS could effectively analyze the mechanical properties and failure modes of segments.The contact between ECC and concrete established through the cohesive model can effectively simulate the interfacial bond slip performance.