Abstract: Based on the Nanjing Weisan Road river-crossing tunnel, and by means of a rational simplified assumption, a calculation model for the flexural behaviors of non-gasket segment joints in shield tunnels is established with and without considering bolt action, and an explicit analytic solution is derived for the joint moment/rotation relationship under different axial forces in different loading stages. Accuracy of the simplified assumption used in the theoretical analysis is verified by comparing the analytic solution without considering bolt action with that of a finite-element numerical calculation model. Additionally, the analytic solution is used to analyze the differences of joint flexural mechanical behavior under an axial force with or without a bolt, to compare the ultimate bending moment of the joints and summarize the function of the bolt, providing a reference value for engineering design.