震后火灾作用下大断面盾构隧道复合管片#br#结构损伤及防水性能分析

为研究大断面盾构隧道复合管片在震后火灾作用下的结构损伤及防水性能损失，利用有限元计算软件abaqus建立复合管片与直螺栓接头的三维实体模型和密封垫压缩的二维数值模型，分析了地震及地震与火灾耦合作用下复合管片混凝土在螺栓孔处刚度损伤分布情况，研究了复合管片钢板在螺栓孔处的屈服分布情况，计算了地震及地震与火灾耦合作用下隧道密封垫防水性能的损失，结果表明：当采用RABT升温曲线模拟火灾时，大震导致的螺栓孔处混凝土刚度损伤在火灾作用后均超过90%，而中震工况在火灾作用后除螺栓孔顶部混凝土刚度损伤低于85%外，其余部分都超过90%；火灾作用导致螺栓孔处钢板屈服；防水密封垫在中震和火灾耦合作用后仍能保持较好的防水性能，但在大震和火灾耦合作用后，防水性能完全丧失。

Structural damage and waterproof performance analysis of composite segment in #br#large section shield tunnels under post-earthquake fire

 In order to study the structural damage and the loss of waterproof performance of large-section shield tunnel composite segment under post-earthquake fire, the finite element calculation software abaqus is used to establish the three-dimensional solid model of a composite segment and straight bolt joint and the two-dimensional numerical model of gasket compression. The stiffness damage distribution of concrete of composite segment at bolt holes and yield distribution of steel plate of a composite segment at bolt holes under earthquake and earthquake-fire coupling are analyzed. The loss of waterproof performance of tunnel gasket under earthquake and earthquake-fire coupling is calculated. The results show that: when RABT heating curve is used to simulate fire, the stiffness damage of concrete at bolt holes caused by a heavy earthquake exceeds 90% after the fire, while the rest exceeds 90% except the stiffness damage of concrete at the top of bolt holes under a moderate earthquake after the fire-Fire causes the steel plate at bolt hole to yield. The waterproof gasket can still maintain good waterproof performance after the combined action of moderate earthquake and fire, but the waterproof performance is completely lost after the combined action of heavy earthquake and fire.