外力作用下错缝拼装盾构隧道粘钢加固结构损伤演化机理研究

It is obviously necessary to take the rational reinforcement to ensure the safety of tunnel lining, as the shield tunnel would exist some serious structure deformation, segment cracks and joint open influenced by the surrounding activities, which decreasing the bearing capacity of the structure. By model tests, numerical simulation and theoretical analysis, the project is aimed to carry out research on the bearing capacity and damage law of the shield tunnel with staggered-jointed and steel-bonded reinforcement structure under different engineering activities. Based on the above work, the key indicators for evaluating the structure safety will be firstly put forward. Then，the failure characteristics of macroscopic deformation and the distribution of the meso-stress for the reinforced structure under different deformation will be discussed, revealing the damage evolution mechanism under external force, to identify the strengthening effect , scope of application and reasonable reinforcement timing for the steel- bonded reinforcement. Finally, we will establish the evaluation model of the ultimate bearing capacity of the section by considering the existing segments damage and the shearing mechanics of the bonding surfaces, and propose the calculation method using the beam-spring model to guide the design of the steel-bonded reinforcement.

由于周边工程活动的影响，地铁盾构隧道结构会出现不同程度变形，甚至引起管片开裂、接缝张开过大等病害，造成服役性能降低，需适时合理加固以确保结构安全。项目拟通过模型试验、数值仿真、理论解析等多种手段，针对堆载、开挖卸载等工程活动对既有盾构隧道错缝拼装结构和粘钢加固后结构的承载性能及损伤规律开展研究，提出结构安全状态评价关键指标；探索既有结构在不同变形状态下采取粘钢加固后的宏观变形破坏特征及细观应力分布发展规律，揭示外力作用下粘钢加固结构的损伤演化机理，探明影响盾构隧道错缝拼装管片粘钢加固效果的关键因素及适用条件、合理加固时机；建立考虑既有管片损伤程度、粘钢-管片粘结面剪切力学行为的截面极限承载力评价模型，提出基于梁-弹簧模型与承载力折减的错缝拼装盾构管片粘钢加固设计计算方法。

随着各城市地铁服役年限增长以及周边活动影响，可能存在衬砌承载能力不足的问题，导致结构发生明显变形，并引发渗漏水等其他病害，严重影响隧道安全运营。由于隧道为典型的地下工程，属于半隐蔽结构，针对衬砌结构的损伤机理分析、健康度评价及维修加固较复杂，而对于多铰不连续圆拱结构的管片衬砌尤甚。因此，盾构隧道的加固处治已成为行业重要需求，也是热门研究方向。本项目采用文献调研、精细化模型试验、数值模拟和理论推导等研究手段，系统研究了盾构隧道错缝拼装管片衬砌的受力变形与破坏过程，明确荷载及结构参数对结构损伤过程的影响规律，提出错缝拼装结构损伤控制指标与评价标准；研究二次受力模式下错缝拼装隧道粘钢加固结构的受力变形特性与损伤演化规律，揭示钢板-管片相互作用机制，提出合理加固时机；研究钢板尺寸、粘结方式等参数对结构承载性能及加固效果的影响，制定加固效果的评判标准，提炼影响加固效果的关键因素，给出合理的加固参数取值建议；建立外力作用下粘钢加固截面极限承载力简易计算方法，为堆载作用下盾构隧道粘钢补强提供科学依据。