Abstract: Based on the incremental analytical solution for the failure history of single ring shield tunnel, the segment joint effect bending moment separation method was derived, and the principle, function, effect, implementation method, verification method and application effect of the moment separation method were analyzed. The research shows that the bending moment separation method can quantify and trace the influence of specific segment joints on the internal force (bending moment) of segments. At the low load level stage, the bending moment separation method can establish an explicit functional relationship between the segment bending moment and the elastic rotational stiffness of the segment joint. At the high load level stage, the incremental expression of the bending moment separation method can trace the internal relationship between the segment bending moment and the nonlinear rotational stiffness of the segment joint. In the failure history of single ring shield tunnel, the influence of segment joints at different locations on the internal force (bending moment) of segments is obviously unbalanced. The increase or decrease of segment bending moment at a specific location and its variation range are dominated and controlled by a few key segment joints. Different segment positions lead to different segment joints that play a leading and controlling role in segment bending moment changes.

Key words: tunnel engineering; segment lining; failure history; separation method of bending moment (SM); U-shape constraint rigid frame

摘要： 基于盾构隧道单环破坏历程增量法解析解，推导了管片接头效应弯矩分离法；分析了弯矩分离法的原理、功能和作用、实施方法、校验方法及应用效果。研究表明：弯矩分离法可以量化和追踪特定管片接头对管片内力（弯矩）的影响；低荷载水平阶段，弯矩分离法可以在管片弯矩与管片接头弹性转动刚度之间建立显式的函数关系；高荷载水平阶段，弯矩分离法的增量表达式可以追踪管片弯矩与管片接头非线性转动刚度之间的内在联系；单环盾构隧道破坏演变过程中，不同位置管片接头对管片内力（弯矩）的影响存在显著的不均衡特征，特定位置管片弯矩的增减及其变化幅度受少数关键的管片接头主导和控制；管片位置不同，对管片弯矩变化形态起主导和控制作用的管片接头不同。

关键词: 隧道工程；管片衬砌；破坏历程；弯矩分离法；U形约束刚臂