路基不均匀冻胀会对高速铁路无砟轨道动力学特性产生重要影响，从而威胁列车高质量运营。因此采用建立的车辆-无砟轨道-路基空间耦合动力学模型，对路基冻胀变形下，不同波长、幅值和行车速度下影响下的轨道动力学特性变化规律进行了研究分析。研究结果表明：当路基冻胀幅值不变时时，随着冻胀波长的增大，车体振动加速度先增大后减小，轮轨垂向力随路基冻胀波长的增大而减小，轮重减载率和脱轨系数随路基冻胀波长的增大而逐渐减小；当路基冻胀波长不变时，随着冻胀幅值的增加，车体振动加速度的峰值逐渐增大，且当路基冻胀幅值为40 mm时，车体轮轨垂向力已经为198.642 kN，并在1.384 s变为0，车体发生了短暂的脱空；轮重减载率和脱轨系数随路基冻胀幅值的增大而增大，且在幅值35 mm时，轮重减载率已经超过限值0.80，对行车的安全性造成了一定影响；行驶速度增加会导致车轨系统动力学指标增大。研究结果可为高速铁路无砟轨道动力学分析与工程病害处置提供重要参考。

Variations in freezing and thawing of the roadbed are known to significantly influence the dynamic behavior of high-speed railway ballast tracks. This phenomenon potentially compromises the safety and efficiency of train operations. A comprehensive vehicle-ballastless track-roadbed spatial dynamic model was employed to examine the effects of different wavelengths, amplitudes, and velocities on track dynamics due to roadbed frost heave. It was found that, with a constant heave amplitude, an increase in wavelength initially boosted and then reduced the car's vibration acceleration. Concurrently, the vertical wheel-rail force diminished as the wavelength extended, leading to a decrease in both the wheel load reduction rate and the risk of derailment. Conversely, when the wavelength was kept steady and the heave amplitude was increased, the car's peak vibration acceleration escalated. At a 40 mm amplitude, the vertical wheel-rail force peaked at 198.642 kN before dropping to zero within 1.384 seconds, resulting in a brief airborne phase for the car. An increase in heave amplitude heightened both the wheel load reduction rate and the derailment coefficient, reaching critical safety thresholds at a 35 mm amplitude. Higher driving speeds intensified the dynamic indicators of the rail system. These insights provide crucial guidance for analyzing dynamic challenges in high-speed railway tracks and addressing structural issues effectively.