Abstract: To investigate the optimal distribution of doublesealing gaskets in largediameter shield tunnels, a refined numerical simulation method that accounts for the detailed structure of joints and plastic damage to concrete is utilized. The effectiveness of the method is validated through a fullscale bending test of joints. The analysis compares the mechanical properties and waterproofing performance of joints with gaskets arranged outside the bolt hole(SGOH) and on both sides of the bolt hole(SGBH). The findings are as follows: (1) The refined simulation accurately reflects the compressionbending performance of the joints. (2) The height, opening, and bolt stress in the compression area of the joint progress through four stages with increasing bending moments, thereby enhancing the bending resistance owing to the improved contact at the outer edge of the compression side. (3) Axial force significantly influences the retention of initial bending stiffness, showing a complex relationship in which stiffness decreases under high axial forces. (4) SGBH exhibits slightly better hogging than sagging performance, while SGOH exhibits significantly better hogging than sagging performance. (5) The arrangement of the doublesealing gaskets affects bending stiffness in relation to axial force, additional bending moments, and the height of the concrete in the core area. (6) Under sagging moments, the waterproofing performance of SGBH is superior to that of SGOH; however, the roles reverse under hogging moments. SGBH, demonstrating superior positive bending and waterproofing performance when at least one side of the gasket is compressed, is found to be more applicable.

Key words: largediameter shield tunnel, segmental joint, doublesealing gaskets, mechanical analysis, numerical simulation