###### Abstract  
To investigate the mechanical characteristics of shield tunnels when openings are made for the construction of cross passages, a series of centrifugal model tests were conducted. The segmental features of the shield tunnel were simulated in the tests, and the influence of different types of openings, namely, rectangular opening, small circular opening, and big circular opening was compared. External earth pressures, structural deformations, dislocations, and structural stresses were monitored during the tests, while the influence of different buried depths was also investigated. The results show that (1) soil arching effect occurred in the overlying soil due to the deformation of the tunnel, and the earth pressure reduction coefficients can guide the tunnel structural design; (2) vertical deformations of the main tunnel and the dislocations between adjacent rings increased with the opening sizes significantly; (3) significant stress concentration occurred close to the openings, and the compressive stress at the inner surface may even exceed the limit strength of the concrete. In summary, the adverse responses of the tunnel increased with the increase of the buried depth and the opening size. Targeted measures should be taken, such as temporary support, longitudinal connections, and high-strength materials near the openings. centrifugal model test; shield tunnel; cross passage; opening type; structural response 2022 22 June 20  
cross passages and main tunnels is a complex three-dimensional structure, which is unrealistic to utilize classical theoretical methods such as beam-spring models or homogeneous ring models to perform analysis. Numerical methods will play a significant role in investigating this issue. [PERSON] and [PERSON] (2015) [16] investigated the structural response of a tunnel when a lateral opening is formed on it, using two-dimensional and three-dimensional finite element analysis. Three-dimensional models were established to investigate the structural behavior of the tunnel openings, and the results showed that a lintel effectively transfers the load above the opening to the adjacent lining rings [8]. [PERSON] et al. (2020) [17] established three-dimensional discontinuous contact numerical tunnel models, including segments, joints, and bolts, to investigate the mechanical characteristics of the mainline tunnel at the opening. However, it is still challenging to accurately simulate the details of the segmental joints such as bolts and bolt holes, mortises and tenons, and sealing liners for problems involving tunnels of a larger scale. Numerical results need to be verified by in situ monitoring data or model tests. Frost heave pressure on the shield tunnel during the construction of the cross passages were monitored using anti-freezing pad-type earth pressure gauges [7]. The maximum measured increment of earth pressures was about 0.2 MPa, smaller than the anticipated value. [PERSON] et al. (2020) [17] conducted field tests of earth pressures, stresses of steel bars and concrete, and the internal forces of bolts on the segmental linings around the opening for the cross passages. The stress characteristics and dangerous sections were identified according to the results of the field tests. Model tests are an effective method to investigate the mechanical characteristics of tunnels. Because shield tunnels are discontinuous segmental structures, it is significant to simulate the segmental features in the model test. Some modeling methods have been proposed to simulate assembled shield tunnels, which can provide a reference for this paper. [PERSON] et al. (2017) [18] employed polypropylene to manufacture model segments, aluminum wires as the circumferential and longitudinal joints, and 1 g scaled model tests were carried out to investigate the progressive structural collapse of the segmental linings. [PERSON] et al. (2019) [19] used plexiglass to simulate the segmental linings, polycarbonate to simulate the longitudinal bolts, and the groove method to simulate circumferential joints.