为对超出设计允许张开量、错台量情况下的盾构隧道接缝防水性能进行评价，探究满足防水要求的密封垫极限张开量、错台量，基于南京和燕路长江隧道工程，选取设计的2种密封垫开展极限张开与极限错台工况下的防水试验，得到密封垫在张开量与错台量超出设计允许值后其防水性能的变化规律。1）在密封垫张开量超过设计允许张开量后，密封垫防水性能随张开量的增大逐步减小，且减小幅度随着张开量的增大逐渐增大。2）错台量超过设计允许错台量后，随着错台量的增大，密封垫的耐水压能力总体呈波动式减小的趋势，直至错台量达到某一临界值，其防水性能迅速下降，直至失效。对于存在张开量与错台量超出设计允许值风险的水下盾构隧道，建议在设计时考虑其在极限工况下的防水性能。

In order to evaluate the waterproof performance of the shield tunnel joint under the conditions that opening amount and dislocation exceed the design allowance, the limited opening amount and dislocation displacement of shield tunnel are discussed so as to meet the waterproof requirements. And then two kinds of gaskets are selected to carry out waterproof test under the conditions of extreme opening amount and extreme dislocation displacement based on the Nanjing Heyan Road Tunnel Project. The variation rules of the gasket waterproof performance under the conditions that opening amount and dislocation exceed the design allowance are obtained as follows: (1) The waterproof performance of the gasket decreases gradually with the increase of the opening amount, and the decreasing range increases gradually with the increase of the opening amount. (2) With the increase of the dislocation displacement, the waterproof performance of the gasket shows a general trend of decreasing by fluctuation until it reaches a critical value, after the dislocation displacement exceeds the critical value, its waterproof performance will rapidly decrease until it fails. For underwater shield tunnels with a risk of opening amount and dislocation displacement exceeding the designed values, it is recommended to consider its waterproof performance under extreme conditions in the design.

〖ＷＴ５ＨＺ〗Keywords:〖ＷＴ５ＢＺ〗 shield tunnel; waterproof gasket; opening; dislocation; extreme waterproof performance