Abstract: Investigating the influence of different loading boundary conditions on the mechanical properties of specialshaped shield tunnel joints is necessary to improve the bearing capability and deformation resistance of tunnel segments. The stressdeformation characteristics of a segmental joint under two loading conditions of the simplysupported beam and steel butterfly type are compared using the finite element method. Further, the correlation transformation formula of joint rotational stiffnesses obtained from jointloading and fullring tests is established. The following conclusions are drawn: (1) Joint deformation increases with an increase in external load in all testing conditions, and the joint deformation derived from the steel butterfly type loading method is larger than that from the simplysupported beam method due to its disregard of the testing specimen′s selfweight in steel butterfly type. (2) The joint rotational stiffness ratios under the simplysupported beam and steel butterfly type loading conditions show a quadratic functional increase and decrease, respectively, as the burial depth increase. (3) The theoretical calculation of the joint′s maximum deflection is not adaptive during its application because the testing specimens are not thin beams.

Key words:  , specialshaped shield, shield segment joint, boundary condition, mechanical properties, rotational stiffness, numerical simulation