Numerical investigation of the compression-bending stiffness of segmental joints with different types of joint surfaces

摘要

The compression-bending stiffness of segmental joints plays a crucial role in the analysis of segment lining structures, and setting reasonable values for joint compression-bending stiffness is a key determinant of the accuracy of mechanical calculations of lining structures. In this study, a three-dimensional refined numerical model of segmental joints is established, and solid elements are used to simulate important components, such as segments and bolts, which essentially reproduce the structural characteristics of the joints and accurately reflect the contact relationship between the segments. Full-scale compression-bending tests are conducted to verify the numerical model, and the compression-bending calculation and analysis of six different segmental joints are performed. The characteristic equations for calculating the compression-bending stiffness of segmental joints with different thicknesses are determined. The results show that the refined three-dimensional model can accurately reflect the compression-bending stiffness of the segmental joints, and the deviations between the numerical and the experimental results appear when damage phenomenon occur on the joint surface. Axial force can improve the compression-bending stiffness of segmental joints, and its influence increases with an increase in the bending moment and decreases with an increase in the thickness. The moment-rotation curves of the joints with different thicknesses are similar. Moreover, increasing the thickness effectively improves the compression-bending stiffness of segmental joints, and the influence increases with increasing bending moment or decreasing axial force. The moment-rotation relationship of a segmental joint has two characteristic curves, I and II, and the type of characteristic curve primarily depends on the structural characteristics of the joint surface. The characteristic equations based on the data-fitting method and the moment-rotation data of segmental joints with different thicknesses can be used to simply and accurately calculate the compression-bending stiffness of segmental joints.