Dynamic Analysis of Metro Vehicle-Track Coupled System under Subgrade Settlement

基于车辆–轨道耦合动力学理论，本文创新性地建立了地铁B型车辆–浮置板轨道–路基耦合系统动力学模型，重点研究了路基不均匀沉降对行车安全的影响。通过系统参数分析发现：(1) 车辆动力响应随沉降波长呈先增后减趋势；(2) 动力响应与沉降幅值呈正相关，控制沉降幅值是确保行车安全的关键；(3) 在典型沉降工况(波长15 m/幅值15 mm)下，车速提升会显著加剧轮轨动态作用、车体振动及轮重减载率。研究成果为城市轨道交通路基沉降防控和列车速度优化提供了重要理论依据。Based on the theory of vehicle-track coupled dynamics, this study innovatively establishes a coupled dynamic model of a B-type metro vehicle-floating slab track-subgrade system, with a focus on investigating the impact of subgrade differential settlement on operational safety. Parametric analysis reveals that: (1) the dynamic response of the vehicle first increases and then decreases with settlement wavelength; (2) the dynamic response is positively correlated with settlement amplitude, indicating that controlling the amplitude is critical to ensuring safe operation; and (3) under typical settlement conditions (wavelength of 15 m and amplitude of 15 mm), an increase in train speed significantly intensifies wheel-rail dynamic interaction, car body vibration, and wheel load reduction rate. The findings provide important theoretical support for subgrade settlement control and train speed optimization in urban rail transit systems.