Effect of soil stiffness on ground vibration amplitude and operational train speed

Using a finite element simulation approach, we studied the influence of ground stiffness on the vibration of a multi-layer ground subjected to high-speed train loading. The study focuses on ground vibration characteristics in cases where the ground contains a soft soil layer with low stiffness, and the effect of increasing ground stiffness on ground vibration amplitude (Umax), critical speed (VTH), and operational speed of the train. The study results show that, in the case of ground with a soft and thick clay layer, owing to its low stiffness, the clay layer mainly influences the dynamic response of the ground. The weaker the clay layer, the lower the VTH and the larger the Umax, thereby limiting the operational speed of the train. When the clay stiffness is increased, the deformation of the clay layer decreases; thus, Umax decreases and VTH increases, thereby increasing the operational speed of the train.