Quantification of ground-vibrations generated by high speed trains in ballasted railway tracks

Abstract

Abstract Ground vibration generated by high speed trains is one of the major challenges in the operation of high speed railway systems. The transit of high speed trains proximate to vibration sensitive structures pose a risk to the structural health of the buildings, especially when the ground vibrations reaching the structure get amplified through the height of the structure at resonant frequencies. A precise quantification of the peak particle velocities (PPVs) is required for analysis of ground vibrations propagating away from the railway track, which also aids in the implementation of suitable vibration mitigation measures if the vibration levels surpass the vibration safety criteria for various classes of buildings. This study investigates the ground vibrations generated by a high speed train wheel in the component strata of a railway embankment during transit at the speed of 200 km/h. Transient numerical analyses were conducted in full scale 3-D railway track models, developed with the geometric cross-sections specified by RDSO, Ministry of Railways in India, for operation of trains in the broad gauge railway track sections. The quantification of vibration velocities were performed in the vertical, longitudinal and lateral axes, and the resultant peak particle velocities were estimated for various strata in the railway embankment and supporting ground. The ground vibrations were found to be oriented mainly in the vertical direction, and the highest vibrations were recorded at the locations when the wheel load was located vertically on top of the section. It was observed that PPVs attenuate with increase in depth from the track level, and with increase in lateral distance from track centreline. High magnitudes of vibration were estimated in the railway embankment and ground when the effect of multiple train wheels superpose. The results also highlight that the horizontal components of ground vibration are significant at farther distances away from the track, implying that foundations of buildings proximate to railway tracks are subject to strong excitations in the horizontal direction.