The correlation between convergence deformation and the safety state of a cross-jointed segmental lining is investigated and clarified. The limitations of convergence deformation as a measuring scale is explored also. Firstly, an analytical algorithm (known as the relative stiffness method, RSM) is developed and verified for tracing the mechanical response of a cross-jointed segmental lining in failure history. Then, an explicit mapping relationship between convergence deformation and the causal factors is established using the RSM. Finally, the root causes of the limitations in using convergence deformation as a scale to evaluate tunnel safety state are discussed, and an alternative quantity, the system performance index (SPI), is proposed. It shows that: (1) The convergence deformation consists of three components induced by segment bending, elastic joint rotation, and joint stiffness attenuating, respectively. The deformation induced by attenuating joint stiffness is dependent on the failure index of segment joints and provides crucial information about the load-bearing state of the segment joints; (2) The components of elastic joint rotation and joint stiffness attenuating are significantly affected by the contact stiffness of the segment joint interface, including the physical and mechanical properties of the packing material. The magnitudes of convergence deformation and its components are not suitable for use as a quantitative scale to evaluate the safety state of the lining due to their inherent drawbacks; (3) The proposed dimensionless variable SPI can eliminate the influence of packing material on the safety state of the segment lining and reflect the comprehensive influence of the failure indexes of the segment joints.

中文翻译：

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基于系统性能指标的交叉节段衬砌安全状态测量


研究并阐明了交叉节段衬砌收敛变形与安全状态之间的相关性。还探讨了收敛变形作为测量尺度的局限性。首先，开发并验证了一种分析算法（称为相对刚度法，RSM），用于跟踪失效历史中交叉连接管片衬砌的机械响应。然后，利用RSM建立收敛变形与因果因素之间的明确映射关系。最后，讨论了使用收敛变形作为评估隧道安全状态的尺度的局限性的根本原因，并提出了替代量——系统性能指数（SPI）。结果表明：（1）收敛变形由节段弯曲、弹性关节旋转和关节刚度衰减三个分量组成。接头刚度衰减引起的变形取决于管片接头的失效指数，并提供有关管片接头承载状态的重要信息； (2)弹性接头旋转和接头刚度衰减的分量受管片接头界面接触刚度的显着影响，包括填料材料的物理和力学性能。收敛变形大小及其分量由于其固有的缺陷，不适合作为评价衬砌安全状态的定量尺度； (3)提出的无量纲变量SPI可以消除填料对管片衬砌安全状态的影响，反映管片接头破坏指标的综合影响。