Serviceability limit states (SLS) of segmental circular tunnel rings, subjected to symmetric loading, may experience asymmetric deformations. This is investigated herein, based on real-scale experiments and structural analysis. Single segmental rings, consisting of six tubbings and six joints, were subjected to 24 point loads, simulating ground pressure until convergence-related SLS were reached. Structural analysis is based on transfer relations, representing analytical solutions of the linear theory of thin circular arches. One symmetric mode and two antisymmetric modes of rigid-body displacements of the investigated segmental rings are described analytically. The vertical-to-horizontal convergence ratio of the symmetric mode is compared with convergence ratios, measured close to the SLS obtained in the tests. This allows for categorization of the tests as symmetric and asymmetric problems. The structural behavior of two asymmetric tests is analyzed by means of a generalized hybrid method. The term “hybrid” applies insofar as the external loading and the data from monitoring of the displacements during the tests are used as input. It is “generalized” in order to allow for consideration of the asymmetric structural behavior, thus abandoning the restriction to symmetry. The relative rotations of the joints are determined such that they refer to symmetric and antisymmetric rigid-body displacements and that the simulated convergences reproduce the measured values. Applying this concept to the two tests, it is shown that the asymmetry develops in a progressive rather than in a stepwise fashion. It refers to different forms of structural behavior of joints that nominally transmit the same normal forces and bending moments. It is concluded that the asymmetry results from small initial imperfections rather than from asymmetric external loading.

分段圆形隧道环的服役极限状态（SLS）受到对称载荷的作用，可能会发生不对称变形。本文基于真实规模的实验和结构分析对此进行了研究。由六个管道和六个接头组成的单节环受到24点载荷，模拟地面压力，直到达到与收敛有关的SLS。结构分析基于传递关系，表示细圆拱线性理论的解析解。分析性地描述了所研究的分段环的刚体位移的一种对称模式和两种反对称模式。将对称模式的垂直到水平收敛比率与收敛比率进行比较，收敛比率的测量接近于在测试中获得的SLS。这允许将测试分类为对称和非对称问题。通过广义混合方法分析了两个非对称测试的结构行为。术语“混合”适用于外部负载并从监测在测试期间的位移的数据被用作输入。它是“一般化的”，以便考虑不对称的结构行为，从而放弃了对称性的限制。关节的相对旋转被确定为使得它们是指对称的和反对称刚体位移和该模拟收敛再现的测量值。将这一概念应用于两次测试，表明不对称性是逐步发展的，而不是逐步发展的。它指的是名义上传递相同形式的关节的不同形式的结构行为。法向力和弯矩。结论是，不对称性是由较小的初始缺陷引起的，而不是由不对称的外部载荷引起的。