不同错台量对复合型密封垫影响及长期防水预测

为研究盾构隧道管片接缝不同错台量对复合型密封垫防水性能的影响,从复合型密封垫遇水膨胀橡胶块二次防水效应出发,在不同错台量条件下分别从密封垫-密封垫接触面和密封垫-密封槽接触面2 个方面分析复合型密封垫防水渐进失效机制,同时基于阿累尼乌斯方程的“P-T-t”三元模型对复合型密封垫长期防水性能进行预测。研究结果表明: 1) 复合型密封垫遇水膨胀橡胶块发生膨胀作用,能够有效增加密封垫间接触面应力,并且密封垫渗漏处主要出现在密封垫与密封垫接触面上; 2) 对于密封垫与密封槽接触面防水能力,随着接缝错台量的增大,对遇水膨胀橡胶块膨胀作用的影响显著; 3) 管片接缝间的张开量和错台量对复合型密封垫的长期防水性能影响显著,并且复合型密封垫长期防水性能随着老化时间先急剧下降后达到平稳状态。

Influence of Different Dislocation Amount on Composite Sealing Gasket and Long-term Waterproofing Performance Prediction

In order to study the influence of different dislocation amount of shield tunnel segment joint on waterproofing performance of composite sealing gasket, the progressive failure mechanism of waterproofing for composite sealing gasket is analyzed from the aspects of gasket-gasket contact surface and gasket-groove contact surface based on the secondary waterproofing effect of water swelling rubber of composite sealing gasket. Meahwhile, the long-term waterproofing performance of the composite sealing gasket is predicted based on the " P-T-t" ternary model of Arrhenius equation. The study results show that: (1) The swelling effect of water swelling rubber of the composite sealing gasket can effectively increase the contact stress of gasket-gasket contact surface, where the leakage point mainly locates on. (2) With the increase of dislocation amount of segment joint, the influence of swelling effect of water swelling rubber on the waterproofing performance of gasket-groove contact surface becomes more obvious. (3) The long-term waterproofing performance of composite gasket is significantly affected by the opening and dislocation amount of segment joint, and it decreases sharply and then becomes stable with aging time of the sealing gasket.