列车运行速度的提高会加剧轨道路基结构的振动，削弱其动力稳定性，并可能产生过大的附加沉降，严重时可导致轨道路基结构失稳破坏，因此，在列车荷载作用下高铁路基结构的动力响应是世界各国高速铁路建设及运营过程中亟待解决的课题。依托典型高速铁路路基工程，利用自主研制的伺服激振控制系统，开展了大比例尺的高铁路基激振模型试验研究，通过激振器模拟列车轮轴循环加载，得到了不同频率激振力作用下路基不同层位的速度的时程变化曲线及幅值空间分布特征；揭示了列车荷载作用下路基速度幅值传递及衰减规律。研究表明，不同频率的激振力作用下路基土体的速度曲线具有明显的周期性峰值；同一频率作用下路基土体中速度幅值沿深度方向不断减小，呈指数衰减趋势，随着深度的增加。研究成果为相应实际工程的设计、施工及运营提供了一定的参考及借鉴。

The improvement of the train operation speed will increase roadbed vibration, and undermine its dynamic stability, and may cause great subsequent settlement; when it reaches the limit value, the roadbed structure will get a bulking failure. Therefore, the dynamic response and disastrous mechanism of subgrade structure under high-speed train load has become an international and urgent research subject in the process of high-speed railway construction and operation. Relying on Wuhan inter-city typical engineering, a large-scale model test of vibration due to train load is carried out by using a self-developed excitation system. By simulating the process of loading with vibration exciter, the time history curve of velocity and the space distribution features of different subgrade layers under the action of different frequencies of vibration force is obtained; and then the velocity transfer and attenuation law of subgrade under the train load is revealed. The experiment results show that. The curve of velocity on subgrade structure has a obvious cyclical peak under different frequencies of vibration force; the speed amplitude on subgrade structure will ever-reduce along the depth direction and show a trend of exponential decay under frequencies of vibration force. The research results will provide a certain reference for designing, construction and operation of practical engineering.