Abstract: The length and stiffness of contact surface at joints have significant effects on the bearing capacity and mechanical behavior of the shield tunnel lining. The conventional surface-surface contact model for segmental joint of shield tunnel shows obvious mesh dependency, which greatly weakens the application of numerical test in practical engineering. With the advantages of the numerical manifold method (NMM) that the mesh is not required to compatible with the geometric physical lines and its powerful unified analysis ability for discontinuous-continuous simulation, the NMM model for segmental joint is established, which can achieve a natural simulation for the discontinuity of shield tunnel lining at joints. Meanwhile, a novel contact model based on virtual-thin-layer (VTL) is proposed for segmental joint, including the generation algorithm for VTL elements with fixed integral points and the nonlinear iterative process for simulating the contact surface. The proposed method features concise algorithm, convenient numerical implementation and stable calculation results, which effectively avoids the mesh dependency. The comparison between the numerical results and the full-scale segmental joint experiment illustrates the efficiency and correctness of the proposed approach. On this basis, the influence of the length of contact surface on the joint mechanical behavior and the rotational stiffness of shield tunnel is further illustrated. The results show that with the decrease of the actual effective contact length, the opening displacement and rotation angle increase exponentially, and the rotational stiffness decreases significantly. Therefore, in the design and construction process of shield tunnel, attention should be paid to the contact length of segments and its assembling precision, and the actual joint stiffness should be analyzed and checked carefully.