关键词: 振动速度, 高铁列车荷载, 桩网复合地基, 模型试验

Abstract: A piled embankment with reinforcement is one of embankments widely used by high-speed railways. The effect of vibration velocity response under train loads of high-speed railways on train running safety and surroundings is crucially important. A large-scale piled embankment model was set up with X-section cast-in-place concrete pile as vertical reinforcement. The vibration performance of the piled embankment under train load of high-speed railways was investigated. The influence of loading frequencies, loading amplitudes, and the number of cycles on vibration velocity of the piled embankment model was revealed in this paper. The results show that it is faster for attenuation of vibration velocity along the transverse direction of the piled embankment. The impact of the embankment on energy dissipation is remarkable, so the effect of vibration induced by train running on surroundings is weaker. The attenuation of vibration velocity along the piled embankment depth is different from the transverse direction of the piled embankment. The piled embankment system shows the greatest attenuation of vibration velocity is from track slab and reinforced concrete base to surface layer of subgrade bed. The gravel cushion with geogrids attenuates less due to shock isolation cushion. The piles in the foundation make attenuation of vibration velocity by train running slower and influence depth deeper. Vibration velocity amplitude increases gradually with the increase of loading frequency, and reaches a peak at 25 Hz. It becomes bigger step by step with the increase of loading amplitude and stays the same with the increase of the numbers of cycles.

Key words: vibration velocity, train load of high-speed railways, piled embankment with reinforcement, model test