Abstract: A mechanical analysis model based on the elastic hinge ring method is established to calculate the internal force of shield tunnel segment lining with nonlinear characteristics subjected to nonuniform loads in composite strata. First, the nonuniform surrounding rock pressures including vertical earth pressure, horizontal earth pressure, and pore water pressure are calculated, and the influence of nonuniform earth pressure on the arch back on structural internal forces is discussed. Second, the ground resistance is determined by the resistance method, and an arc-shaped lateral resistance distribution assumption is adopted. The force method is applied to derive the analytical solutions for axial force, shear force, and bending moment of segment lining under various load conditions. Last, a case study is conducted on the Beijing Metro Line 10, the MATLAB and ANSYS software are adopted to obtain the analytical solutions and numerical solutions of internal forces of segment lining. Meanwhile, sensitivity analysis is conducted on key parameters including joint stiffness, soil resistance coefficient, and overburden thickness. The main conclusions are drawn as follows: (1) The analytical solutions agree well with the numerical solutions in distribution rules, verifying the rationality of the proposed model and derivation method. (2) The axial force of segment lining is compressive throughout the structure and increases uniformly from the crown to the invert, presenting an obvious force transfer characteristic. (3) The shear force is zero near the crown and arch waists, and shows an abrupt variation at the invert. (4) The bending moment is positive near the crown and invert, and negative at the arch waists. (5) Joint stiffness exerts the most remarkable effect on bending moment. The soil resistance coefficient has a great influence on bending moment when its value is small, and the peak bending moment decreases with increasing coefficient. The overburden thickness mainly governs the maximum bending moment.

Key words: shield segments, nonuniformly distributed load, elastic hinge ring method, segment internal forces, analytical solutions