高速铁路桥梁-轨道系统大震破坏机制与功能可恢复设计方法研究

In order to meet the requirements of the moving smoothness and safety of high-speed train, the bridge stiffness plays a key role in the design of high-speed railway (HSR) bridge in China. The current seismic design of HSR bridge under strong earthquakes only considers the seismic performance and structural ductility of piers and bearings, and the track structure is not included in the seismic design, and moreover the resilient-based design related with the moving train is also not taken into account. Therefore, the economic loss and social impact brought by line interruption in strong earthquakes will be enormous, and the interruption will also hinder the post-disaster emergency relief. Based on this point, the research on resilience-based design method and failure mechanism of high speed railway bridge-track system under maximum considered earthquake is carried out. The main work is as follows: based on the research investigation, a series of tests of piers and bearings of high-speed railway bridge completed by our research group, and by statically testing the seismic performance of track structure, the hysteresis curves and failure characteristics of pier, bearing and track structure are given, and then the failure rule and mechanism of HSR bridge-track system are figured out; the influence of failure mechanism of HSR bridge-track system on function resilience under maximum considered earthquake is studied, and corresponding performance levels and indexes related with the resilience are provided, and then design performance objective are also established, and by setting seismic response reduction and isolation device instead of the bearing, the energy-based design method for performance design of HSR bridge-track system is proposed; the typical HSR simply supported bridge and continuous bridge are designed by the proposed resilience-based design method, and the validity of the design method is verified by numerical analysis and hybrid test of HSR bridge-track system.

为满足高速铁路行车平顺性和安全性要求，我国高速铁路桥梁设计以刚度控制为主，大震设计仅验算桥墩、支座等抗震性能与延性，未考虑轨道结构震致破坏，未考虑与行车相关的大震功能可恢复设计，强地震下线路中断将导致重大经济损失和深远社会影响，并影响灾后紧急救援。基于此，本项目拟开展高速铁路桥梁-轨道系统大震破坏机制与功能可恢复设计方法研究，如下：根据文献调研和课题组已完成高铁桥梁桥墩及支座系列试验，开展轨道结构拟静力试验，获取桥墩、支座、轨道结构等地震易损构件滞回曲线和破坏机理，研究明确高铁桥梁-轨道系统大震破坏特征与机制；研究高铁桥梁-轨道系统破坏机制对大震功能可恢复性能的影响，明确大震功能可恢复的性能水准和指标，建立相应性能目标，基于支座处设置减隔震，提出用于高铁桥梁-轨道系统韧性设计的能量方法；开展典型高铁简支梁桥和连续梁桥的大震功能可恢复设计，并通过数值仿真和混合试验验证所提出设计方法的有效性。

考虑到我国高速铁路桥梁设计往往忽视轨道板的破坏，且以桥墩刚度控制设计为主，对于桥墩延性以及功能可恢复设计考虑不足，强地震下可能存在高铁桥梁-轨道系统的功能失效和塑性破坏。基于此，本项目开展系统研究工作，在以下方面取得了重要结果。（1）系统研究了在中远场地震动和近场地震动作用下桥梁-轨道系统的强震破坏机理：研究了不同场地类型下桥墩破坏特征，提出了不同高度桥墩弯剪破坏的剪切强度下降模型，揭示了桥梁-轨道系统的强震破坏特征，指出了轨道结构的刚度约束效应以及强震破坏次序，对比了中远场地震动和近场地震动脉冲效应及高频振动所带来的桥梁-轨道系统破坏特征的差异，指出地震动高频特征导致桥梁-轨道系统破坏，脉冲效应影响并不明显；（2）建立了可表征列车脱轨的轨面速度谱强度指标和轨道结构简化非线性弹簧模型：所提出了速度谱强度指标可用轨面速度强度表征列车脱轨极限状态，通过物理试验和仿真与日本静止列车及国内学者理论结果比对，验证了该指标的有效性，提出了Ⅱ型板和Ⅲ型板的弹塑性破坏特征模型，可用具有物理含义关键点的非线性弹簧描述轨道结构的破坏过程；（3）研发了地震下桥上行车物理试验模拟技术和“数值桥-试验车”数物融合混合试验模拟技术及精细多平台仿真技术：按照1:10缩尺比例研发了国际首套桥上列车震致脱轨的物理试验技术和装置，研发了列车-轨道-桥梁的混合试验实时模拟技术，提出了移动度哈梅积分和物理信息神经网络实时计算方法，研发了自适应复合控制等控制算法，提出了离线迭代混合试验方法，解决了理论结果缺乏验证的难题；（4）提出了高铁桥梁-轨道系统基于性能的设防目标，深化了大震功能可恢复设计，并提出了能量设计方法：弥补了当前规范对于高铁桥梁-轨道抗震目标不明确的缺陷，通过基于能量法的支座优化设计实现了多地震水准的准确设防；（5）研发了地震下桥上行车安全的X型钢条等多种耗能减震器、基于速度谱指标优化设计的调谐吸能装置。