A ballasted track system is a multi-layer elastic structure that exhibits complicated mechanical behaviour under trainloads. Therefore, accurate modelling of these structures is essential for revealing the characteristics of train-track-bridge interaction. This study aims to study the dynamical interaction characteristics of a heavy-haul train-track-long-span bridge system (HTTLSBS) by developing an effective modelling approach. First, based on D’Alembert principle, the vibration equations of a heavy-haul train subsystem are derived by adequately considering the mechanical behaviour of its components. Then, a highly efficient modelling methodology for a large-scale track-bridge subsystem is developed based on the component mode synthesis (CMS) method, which considers both the elasticity and load-transfer characteristics of the ballasted track and long-span bridge subsystems. The train, track, and bridge subsystems are coupled with a nonlinear wheel-rail contact relationship and an improved track-bridge interaction relationship, respectively. Subsequently, the dynamic responses acquired from numerical simulations are comprehensively compared with field test data, validating the effectiveness of the developed methodology. Suitable modal truncation frequencies of the long-span bridge model with the CMS method are also determined. On this basis, the advantages and significance of the proposed approach are demonstrated by comparing it with traditional modeling methods. Finally, by applying the proposed approach, several crucial parameters of the ballasted track system are suitably selected with the aim of reducing the vehicle-track-bridge dynamic interaction. The research results may provide useful guidance for the theoretical modelling and optimal design of HTTLSBS.

中文翻译：

---

考虑改进的轨道-桥梁关系的重载列车-轨道-大跨桥梁相互作用的新型建模方法


有碴轨道系统是一种多层弹性结构，在列车载荷下表现出复杂的机械行为。因此，这些结构的精确建模对于揭示火车-轨道-桥梁相互作用的特征至关重要。本研究旨在通过开发有效的建模方法来研究重载火车轨道大跨桥梁系统（HTTLSBS）的动态相互作用特性。首先，基于达朗贝尔原理，充分考虑重载列车子系统部件的力学行为，推导了重载列车子系统的振动方程。然后，基于组件模式综合（CMS）方法，开发了一种针对大型轨道桥梁子系统的高效建模方法，该方法同时考虑了有碴轨道和大跨桥梁子系统的弹性和荷载传递特性。列车、轨道和桥梁子系统分别通过非线性轮轨接触关系和改进的轨道桥相互作用关系进行耦合。随后，将数值模拟获得的动态响应与现场测试数据进行全面比较，验证了所开发方法的有效性。还确定了采用 CMS 方法的大跨桥梁模型的合适模态截断频率。在此基础上，通过与传统建模方法的比较，论证了该方法的优点和意义。最后，通过应用所提出的方法，适当选择有碴轨道系统的几个关键参数，以减少车辆-轨道-桥梁的动态相互作用。研究结果可为HTTLSBS的理论建模和优化设计提供有益的指导。