为深入探究盾构隧道机械法联络通道破洞响应力学机制，依托足尺试验对“玻璃纤维筋混凝土管片+钢混复合管片”的联络通道洞口结构开展三维有限元数值模拟分析，考虑初始、预撑、切削、成洞及拆撑5个关键施工步骤下管片的受力特征，并通过试验数据比对验证模拟结果的准确性。计算结果表明： 在联络通道洞口破洞过程中主隧道开洞区域出现明显应力集中，破洞后切削环出现“悬臂”变形，最大弯矩、轴力出现在洞口两侧邻近管片，混凝土损伤主要分布在拱顶内弧面以及开洞侧拱腰的外弧面。在此基础上，依托杭海城际铁路工程实践提出“环梁加固”洞门结构模型，并对比2种结构在破洞施工过程中主隧道管片的力学响应，发现2种不同结构在轴力和弯矩方面的差异较小，但后者衬砌位移更小。认为外浇环梁能够显著提升主隧道纵向结构刚度，通过环梁传力能有效控制管片切削过程中相邻环之间的差异变形。

To explore the mechanical response of tunnel portal in mechanized construction of cross passage of shield tunnel, a threedimensional finite element numerical simulation is conducted on tunnel portal structure of cross passage, i.e.,  reinforced concrete segment reinforced by glass fiber + reinforced concrete composite segment, based on fullscale test, which considers the stress characteristics of segment during start, presupport, cutting, tunnel forming, and support dismantling process. Then the test data is compared with simulation results to validate its accuracy. The calculation results show the following: (1) The opening area at the main tunnel shows obvious stress concentration during cross passage breaking. (2) The cutting deforms after the opening is broken. (3) The maximum bending moment and axial force appear in the adjacent segments on both sides of the opening. (4) The concrete damage is mainly distributed in the inner camber of the arch crown and the outer camber of the arch waist at the opening side. Furthermore, a tunnel portal structure model of ring beam reinforcement is proposed, whose mechanical response during tunnel portal breaking of cross passage is compared with the abovementioned one. The comparison results show that the axial force and bending moment of the two structures vary little, but the lining displacement of the ring beam reinforcement structure is much smaller. The results demonstrate that the longitudinal structural stiffness of the tunnel can be improved by ring beam, and the differential deformation between segments can be effectively controlled during segment cutting process.