强震作用下大断面海底盾构隧道管片环缝防水性能

Waterproof Performance of Segment Joints of Large Section Subsea Shield Tunnel Under Strong Earthquake

为探明强震作用下导致的盾构隧道管片接缝大张开情况下的防水性能,以在高烈度区修建的大断面海底盾构隧道——苏埃通道工程为依托,通过有限元数值分析建立纵向等效刚度模型及隧道全长震动分析模型,确定了高烈度区强震作用下管片环缝的震动张开量,并根据张开量的大小类比既有大断面盾构隧道防水标准,建立了高烈度区强震作用下大断面盾构隧道环缝防水指标;通过接缝防水试验,优化了密封垫及沟槽截面尺寸,并据此提出了强震作用下的大断面海底盾构隧道管片环缝防水的合理形式。结果表明:强震作用时三段硬岩凸起处、接收井处及多地层交互处环间接缝张开量显著大于其他区段,其环间张开最大值远大于既有大断面盾构隧道的张开量,应对此类区段采取特殊的抗震措施,降低环缝张开量;仅增加密封垫的厚度达不到强震条件下的防水要求,并且密封垫的压缩应力会急剧提高,于管片拼装不利,同时提高密封垫截面并加深密封垫沟槽可提高抗水压能力,且密封垫的压缩应力能达到一个合理值,不影响管片的拼装效率。研究结果可为苏埃通道工程及类似工程的管片接缝防水设计提供参考。

In order to ascertain the waterproof performance of segment joint with large opening in the shield tunnel under the action of strong earthquake,on basis of large section subsea shield tunnel,namely,Su＇ai Channel project built in highly seismic regions,the longitudinal equivalent stiffness model and the full length vibration analysis model of the tunnel were established by the finite element numerical analysis and the vibration opening amount of the segment ring under the strong earthquake area was determined.By the analogy of waterproof standard for large section shield tunnel according to the amount of the opening,the waterproof index of large section shieldtunnel in the highly seismic region under strong earthquake was established.The size of the gasket and groove was optimized through the waterproof test of the joint.Whilst,the reasonable form of waterproof of segment joint of large section subsea shield tunnel under strong earthquake was put forward.The results show that the opening amount of joints between rings on the three bumps of hard rock,in the receiving well and in the section where multilayer interaction takes place is significantly higher than that in other sections under strong earthquake.The maximum value of the ring opening is much higher than that of the existing large section shield tunnel.Special seismic measures should be taken to reduce the opening amount of the ring seam.The requirements of waterproof under strong earthquake can＇t be met by increasing the thickness of the seal.Moreover,the compressive stress of the seal has increased sharply,which will be detrimental to the assembly of the segment.The hydraulic resistance can be improved by raising the sealing gasket section and deepening the sealing groove at the same time. When the compressive stress of the seal reaches a reasonable value,the assembly efficiency of the segment cannot be affected.The research results can provide references for the waterproof design of segment joints for the Su＇ai Channel project and similar projects.