Improvement of the critical speed in high-speed ballasted railway tracks with stone columns: A numerical study on critical length

The pressure to achieve a higher speed of train operation has increased in the last few years due development high-speed railway lines. In presence soft soils, this increase is not possible without undertaking soil improvement measures, since critical lower than desired operation. One most widely used techniques that stone columns. relation these concept length which, up now, only been studied for static cases. This research focuses, first time, on enhancement railways with columns and special reference length. Moreover, others parameters such as: maximum rail displacement Dynamic Amplification Factor (DAF) are also studied. Analysing three profiles ground representative it can be observed how effect relevant, showing different respect above, restrictive one being which corresponds speed. influence other effectiveness columns, as area replacement ratio, dynamic bulb existing stiffness analysed discussed.