Abstract:

The cylinder thrust force and bolt pretightening force are selected as the main research construction loads, the structure model and rubber seal model are established by ANSYS, and the segment opening amount under construction load and the waterproofing performance under the corresponding segment opening amount are studied by taking the shield section of municipal project of Shenzhen Metro International Exhibition Center for example. The relationship between construction load and waterproofing performance of segment is obtained. The research shows that: (1) The cylinder thrust force has great influence on the circumferential joint and little influence on the longitudinal joint and it will increase the opening amount of circumferential joint. (2) The waterproof performance of rubber seal gasket between segments increases first, and then decreases with the increase of segment opening amount; the risk of seepage exists when the opening amount is 2 mm or more than 6 mm. (3) By taking 2 mm opening amount as calculation control standard, the cylinder thrust force reduces the waterproofing performance of the segment in the straight line section by 8% and the curved section by 15%. (4) The increase of the pretightening force of the bolt can slightly improve the waterproofing performance of the segment in the straight line section, but has no effect on the waterproof performance of the segment in the curved section. The waterproofing performance of segments in curved section is worse than that in straight under the same construction form.

Key words: small radius curved tunnel, shield segment, construction load, segment opening amount, numerical simulation