Abstract: In order to probe into the 3D mechanical behaviors of shield tunnel segmental linings,a shell-spring-contact model for load and structure interaction was set up by using thick shell,spring,solid and contact elements to analyze forces acting on shield tunnel segments.Several special features were considered,including extrusion between segments,occlusion between segments and bolts,subgrade reaction between radial and tangential components,rotational stiffness of ring joints under positive and negative bending,and approximate insertion angle of the key segment.A numerical example shows that there exists a little difference between the calculational results based on the shell-spring-contact model and a beam-spring model,and the distributions of axial and shear forces on the shell have obvious spatiality.