地下爆炸波冲击下隔震连续梁桥动力响应分析

针对地下隧道内意外爆炸所引起的地下爆炸波的冲击作用，对带有摩擦摆支座的隔震连续梁桥进行动力响应分析，同时考虑土与桥墩基础以及桥台之间的动力相互作用．在土-结构动力相互作用分析中，采用有限元、无穷元和梁元等多种数值模型相耦合的方法建立了由地下隧道及其周围包含河道的有限土区、远场半无限土区以及跨越河道的摩擦摆支座连续梁桥等3部分构成的整体计算模型；在摩擦摆支座隔震分析中，提出了连续摩擦力模型以取代库仑摩擦力模型，从而避免跟踪啮合滑移的过渡边界并可减小计算误差．通过数值仿真以及与Lysmer透射边界法和修正阻尼透射边界法的计算结果进行对比分析，验证了所建立的耦合方法的有效性；通过与板式橡胶支座和刚性球铰支座的隔震效果进行对比分析，揭示了摩擦摆支座连续梁桥的顺桥向隔震效果以及不同参数对隔震效果的影响．分析结果为城市地下隧道及桥梁的抗爆设计的理论研究和工程实践提供了重要的参考依据．

Dynamic Response Analysis of Base-Isolated Continuous Girder Bridges Subjected to Underground Explosion Waves

The dynamic response analysis of an base-isolated continuous girder bridge with friction pendulum (isolation) supports, subjected to the underground explosion waves caused by accidental explosion inside an (underground) tunnel,was performed.The dynamic interactions between the soil and the bases of piers and the (abutments) were considered. For analysis of the soil-structure dynamic interaction, an integral model was (established) by coupling various numerical models such as the finite element, the infinite element and the beam element.The integral model consisting of a tunnel and its neighboring finite soil including a river channel, the surrounding semi-infinite soil, and a continuous girder bridge with the friction pendulum isolation supports, crossing the river channel. In the analysis of the isolation with the friction pendulum supports, a continuous friction model instead of the traditional Coulomb friction model was proposed in order to avoid tracing the (transient) boundary between meshing and sliding and to reduce the calculated error. The validity of the presented coupling method was proved through numerical simulation and comparison with the calculated results by using the Lysmer viscous boundary method and the modified Lysmer viscous boundary method respectively. And, the isolation effect of the friction pendulum isolation supports on the longitudinal dynamic responses of bridge and the influences of different isolation parameters on the isolation effect were discovered through the comparative (investigation) of the isolation effects of the ordinary rubber supports and the fixed-hinge supports.The obtained analytical results provided an important reference for the theoretical research and engineering practice of the (explosion-resistant) design for the bridges and the underground tunnels in cities.