Effect of embankment conditions on ground vibrations induced by high-speed lines

Over the years, the rapid growth in railway infrastructure has led to numerous environmental challenges. One such significant issue is ground-borne vibration induced by high-speed lines. Although the effect of a train travelling on at-grade line was intensively studied in the past, research of the effect of embankment is scarce. This paper presents a numerical prediction of the ground vibration levels with applications on high-speed rail infrastructure. First experimental tests are studied: the effect of embankment on the generated railway ground vibrations is analysed using two different sites presenting the same soil configuration but with a different track earthworks profile (one embankment and one at-grade). In-situ tests were performed to determine soil dynamic parameters by using non-intrusive methods and to collect surface vibration in the three directions due to several train passing. The latter are of sufficient interest so as to be used to validate the proposed prediction model based on a finite element approach and suitable for complex geometries. This study is completed by a numerical analysis in order to better discern and understand the parameters and configurations that influence ground surface motion. It was found that the embankment case causes lower peak particle velocities than the at-grade case. Particular attention was paid to the softness of the embankment compared to the rest of the soil, showing that the embankment acts as a waveguide thus trapping energy within it.