盾构隧道FRP网格加固机理及可恢复性优化方法

Transverse deformation is an important root of the shield tunnel disease. During operation, how to control lateral deformation scientifically and rationally is the core issue for shield tunnel maintenance. The current research and practice regarding lateral deformation control in inner surface is subjected to some deficiencies in that vague of interface failure mechanism, limited selection of strengthening methods and lack of optimization method. In this project, by using FRP Grid in inner surface, it is to conduct both fundamental and application-oriented research focusing on the strengthening mechanism and optimization method based on resilient theory for lateral deformation control. The mathematical model of interface stress will be established based on the complex structure theory, through which the failure mechanism will be revealed and then control measures will be proposed. The numerical method and calculation theory of bearing capacity will be established, and the action mechanism will be revealed for shield tunnel strengthened by FRP grid in inner surface; The recoverability comprehensive model considering the carrying capacity, horizontal convergence and joint deformation will be put forward; The vulnerability and recovery efficiency of tunnel structure will be studied with similar experiment and numerical simulation. Finally, an optimization method for FRP grid strengthening method in inner surface based on resilient theory will be proposed. The theories and methods developed in this project can enrich the internal surface strengthening methods, deepen the understanding of strengthening mechanism in inner surface and realize the scientific optimization of strengthening methods, which has important social significance and extensive engineering application prospect.

横向变形是盾构隧道病害的重要根源，如何科学合理地控制隧道横向变形是地铁运营安全维护的核心热点问题。针对横向变形内表面加固理论和实践中“界面失效机制认识不清，加固方法选择有限，科学优化方法欠缺”的不足，开展盾构隧道横向变形FRP网格内表面加固作用机理及可恢复性优化方法的基础理论和应用研究。采用复合结构理论建立管片内表面加固界面应力数学模型，揭示界面失效机制并提出控制措施；建立FRP网格加固盾构隧道数值方法和承载性能计算理论，采用相似实验和数值模拟揭示FRP网格加固盾构隧道的作用机理；引入可恢复性理论，建立考虑承载力、横向收敛和接头变形的盾构隧道可恢复性综合评价模型；采用相似实验和数值模拟研究隧道的易损性和恢复效能，建立基于可恢复性原理的FRP网格内表面加固优化方法。研究成果可丰富隧道内表面加固方法体系，深化内表面加固作用机制认识，实现加固方法科学优化，具有重要的社会意义和广泛的工程应用前景。

盾构隧道已经成为了城市的生命线工程，但运营期的很多盾构隧道结构产生了严重的病害，极大地影响了轨道交通的正常运营和乘客的生命财产安全。横向变形是盾构隧道病害的根源，如何科学合理地控制隧道横向变形是地铁运营安全维护的核心热点问题。针对横向变形内表面加固理论和实践中“界面失效机制认识不清，加固方法选择有限，科学优化方法欠缺”的不足，开展盾构隧道横向变形FRP网格内表面加固作用机理及可恢复性优化方法的基础理论和应用研究。项目综合实验研究、数值模拟、理论分析和现场实践等研究手段，取得了以下研究成果：建立了盾构隧道管片内表面加固的界面应力模型，提出了基于内聚力模型的界面模拟方法，揭示了盾构隧道加固内表面界面破坏萌生-扩展-破坏的失效演化全过程；提出了管片接头两端锚固和锥形板端的界面破坏有效防控措施；阐明了FRP网格内表面加固提升盾构隧道承载性能的变化规律：FRP网格能有效控制隧道横向变形和顶拱接头张开量，地层刚度系数越小，控制效果越优异；加固前隧道已有变形会造成FRP网格产生损失应变，已有变形越小，损失应变越小，控制效果越好；FRP网格用量提高，控制效果增强，但FRP网格利用率降低，因此增强趋势减弱；建立了FRP网格提高盾构隧道管片接头刚度计算理论：FRP网格可以有效提高接头抗弯刚度，抑制接头张开量和转角，并且效果随接头偏心距离增大而提高；提出了将轴力-弯矩曲线与坐标轴围成的面积作为管片正截面承载性能的评价指标，建立了内表面加固的正截面承载性能计算理论，探明了盾构隧道正截面内表面加固承载性能演化规律；建立了综合考虑管片横向收敛和正截面承载性能的盾构隧道加固可恢复性模型并有效指导了现场实践。研究成果深化了盾构隧道管片内表面加固作用机制认识，丰富内表面加固方法体系，为盾构隧道加固的科学优化和安全控制提供了基础。以第一作者或通讯作者发表 SCI 检索论文 10 篇，EI检索论文6篇；授权专利10项；获省部级奖项2项。