局部高温下粘钢加固盾构隧道衬砌的破坏机制及防控措施研究

For shield tunnels whose transverse convergence deformation exceeds the requirements while limited by the tunnel construction boundary, the bonded steel plate reinforcement method is being promoted and applied gradually. Due to a series of unexpected accidents such as short circuit of electric circuit, equipment failure and artificial arson, shield tunnel reinforced by bonded steel plate may suffer from partial high temperature effects, resulting in the subsequent bearing performance of the shield tunnel being weakened or even structural safety being threatened. Therefore, this project intends to study the failure mechanism and prevention-control measures of shield tunnels reinforced by bonded steel plate after exposure to partial high temperature, so as to ensure the effectiveness of bonded steel plate reinforcement and the safety of resistance to high temperature of shield tunnels. First of all, experiments will be carried out according to three stages: the epoxy resin and geopolymer adhesive materials stage, model components stage and the staggered joint assembled prototype system stage. After exposure to partial high temperature, mechanical behavior of shield tunnel structure system reinforced by bond steel plate will be revealed as well as its high temperature resistance capacity and failure mechanism. Meanwhile, combined with the experimental results, a three-dimensional detailed numerical model will be established and a series of numerical simulation tests considering related influencing factors will be carried out, so as to obtain the quantitative relationship among duration time and acting area of high temperature, the ultimate bearing capacity of the shield tunnel and bonding failure range. Finally, based on the above test results, this project will put forward the bonded steel plate reinforced shield tunnel after exposure to partial high temperature fortification standards and targeted prevention-control measures.

针对横向收敛变形超标且受建筑限界制约的盾构隧道，粘钢加固补强工法正在逐步推广应用。一旦出现电气线路短路、设备故障、人为纵火等突发事故，粘钢加固盾构隧道将遭遇局部高温作用，诱发管片与钢板界面粘结胶材的力学性能急剧劣化，导致盾构隧道后续承载性能降低甚至危及结构安全。为此，本项目拟针对局部高温条件下粘钢加固盾构隧道的破坏机制及防控措施开展研究，以保障盾构隧道粘钢加固的有效性及耐高温安全性。首先，针对环氧树脂和地聚物粘结胶材、模型构件、错缝拼装原型体系三个层次开展试验，揭示局部高温作用下粘钢加固盾构隧道结构体系的力学行为、耐高温能力及失稳破坏机制；其次，结合试验结果，通过三维精细化模拟手段对相关影响因素开展系列数值仿真试验，获得盾构隧道极限承载力、耐高温持时与局部高温作用区域、粘结失效范围的量化关系；最后，基于以上试验成果，提出粘钢加固盾构隧道的耐高温设防标准以及相适应的防控措施。

针对横向收敛变形超标且受建筑限界制约的盾构隧道，粘钢加固工法正在逐步推广应用。一旦出现电气线路短路、设备故障等突发事故，粘钢加固盾构隧道将遭遇局部高温作用，诱发管片与钢板界面粘结胶粘的力学性能急剧劣化，导致盾构隧道承载性能降低甚至危及结构安全。基于上述目的，项目团队首先对高温作用下钢板与混凝土粘接性能失效规律进行了研究，然后开展了粘钢加固管片接头高温下承载性能足尺试验。在此基础上，进一步完成了考虑结构胶粘剂失效的单环管片模型试验及数值反演验证。综合试验结果以及数值模型结果，分别从环氧树脂和地聚物粘结胶材、模型构件、错缝拼装原型体系三个层次对由于局部高温而导致钢板加固管片结构的结构胶粘剂失效的失效范围、粘贴钢板加固效果的下降及最终管片结构剩余承载力之间的量化关系进行了探讨。最后，基于以上成果，提出了粘钢加固盾构隧道的耐高温设防标准以及相适应的防控措施。