管片接缝螺栓孔外侧双道密封垫合理布置型式研究

Layout Modes of Double Sealing Gaskets Outside Bolt Hole of Segment Joint

目前普遍使用的单道三元乙丙橡胶密封垫防水型式无法满足水下盾构隧道管片接缝防水新要求,而既有的双道密封垫防水体系受螺栓孔防水性能的限制无法充分发挥其应有的防水性能。依托江阴靖江长江隧道,提出将双道密封垫均放置于螺栓孔外侧的新型防水体系,并结合设计对比分析双层密封垫连续布置和间隔布置2种型式的防水性能。基于不同的沟槽布置形式,设计可更换内胆的T字缝耐水压测试设备,并开展室内物理模型试验,研究结果表明:1)螺栓孔外侧连续布置的双道密封垫的防水性能表现不佳;2)在讨论连续布置双道密封垫的匹配策略时,发现“外主内辅”对整体防水性能有2.02%的提升,“外辅内主”则导致整体防水性能下降4.71%;3)较单道密封垫,螺栓孔外侧间隔布置双道密封垫防水体系的整体防水性能可提升9.68%~16.13%。

Currently, the frequently used single ethylene propylene diene monomer sealing gasket cannot fulfill the segment waterproofing requirements of an underwater tunnel any more, and the double sealing gaskets waterproofing system is constrained by the waterproof performance of bolt holes. Hence, a review of the Jiangyin-Jingjiang Yangtze river tunnel is conducted, a new waterproof system with double sealing gaskets placed outside the bolt holes is proposed,and the waterproof performance is analyzed under two layout modes of continuous arrangement and interval arrangement. Additionally, based on various groove layout modes, a T-slot water pressure test equipment with a replaceable liner is designed, and indoor physical model tests are performed. The findings of the study reveal the following:(1) The waterproof performance of the double sealing gaskets arranged continuously outside the bolt holes is not as strong as anticipated.(2) The double sealing gaskets with a layout mode of "outer as main and inner as auxiliary" can significantly improve waterproof performance by 2.02%, whereas that with a layout mode of "outer as auxiliary and inner as main" will result in a 4.71% decrease in total waterproof performance.(3) Compared with a single sealing gasket, double sealing gaskets arranged at intervals outside the bolt holes improve waterproof performance by 9.68% ~16.13%.