Voids and lining defects can be regarded as typical diseases in tunnel structure. In this paper, three-dimensional numerical modeling was conducted to explore the safety state and the failure behavior of degraded tunnel structure with compound diseases. At first, the three-dimensional distribution of lining inner force was explored. Subsequently, the distribution of safety factors with the reinforcement of the fiber reinforced plastic (FRP)-polymer cement mortar (PCM) method was evaluated. Finally, the plastic failure behavior of tunnel lining under various deterioration degrees and ground class was comprehensively investigated. The results indicate that the safety factors exhibit the positive relation with the grade of the FRP grids. In addition, plastic failure characteristics are not only affected by the lining deterioration degree but also the ground class. The higher the lining deterioration degree, the easier it is for tensile-shear plastic failure within the compound disease zone; otherwise, the more likely it is for tensile plastic failure. The lower the grade of the ground class, the easier it is for tensile-shear plastic failure within the compound disease zone.

空洞和衬砌缺陷是隧道结构中的典型病害。本文通过三维数值模拟研究了退化隧道结构的安全状态和复合病害的破坏行为。首先探索了衬砌内力的三维分布。随后，评估了纤维增强塑料 (FRP)-聚合物水泥砂浆 (PCM) 方法加固的安全系数分布。最后，综合研究了不同劣化程度和地基等级下隧道衬砌的塑性破坏行为。结果表明，安全系数与玻璃钢格栅等级呈正相关。此外，塑性破坏特性不仅受衬里劣化程度的影响，还受地面等级的影响。衬里劣化程度越高，复合病区内越容易发生拉剪塑性破坏；否则，拉伸塑性失效的可能性就越大。地面等级越低，复合病区内越容易发生拉剪塑性破坏。