Theoretical treatment of ground vibrations from high speed railways (original) (raw)
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Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2000
The increased speeds of modern trains are normally accompanied with increased transient movements of the rail and ground, which are especially high when train speeds approach some critical wave velocities in the track±ground system. These transient movements may cause large rail deflections, as well as structural vibrations and associated noise in nearby buildings. There are two main critical wave velocities in the track±ground system: the velocity of the Rayleigh surface wave in the ground and the minimum phase velocity of bending waves propagating in the track supported by ballast, the latter velocity being referred to as the track critical velocity. Both these velocities can be exceeded by modern high-speed trains, especially in the case of very soft soil where both critical velocities become very low. The discussion in this paper focuses on the effects of transient rail deflections on associated ground vibrations in the cases of train speeds approaching and exceeding Rayleigh wave and track critical velocities. The obtained theoretical results are illustrated by numerical calculations for TGV and Eurostar high-speed trains travelling along typical tracks built on soft soil.
Effects of track properties on ground vibrations generated by high-speed trains
Acta Acustica united with Acustica, 1998
Increase in speeds of railway trains is usually accompanied by higher levels of generated ground vibrations, which are especially large if train speeds exceed the velocities of Rayleigh surface waves in the ground. Therefore, it is vitally important to consider possible methods of protecting the built environment against intensive ground vibrations associated with high-speed trains. The present paper investigates the effects of some geometrical and physical properties of the track, i.e., those of track bending waves and distance between sleepers, on railway-generated ground vibrations. It is shown that the effect of track bending waves may cause increase in amplitudes of ground vibrations generated by trains travelling at speeds higher than the velocities of Rayleigh surface waves in the ground (trans-Rayleigh trains) if the train speeds approach the minimal phase velocity of track bending waves. This implies that tracks with low minimal phase velocities of bending waves should be avoided. The reduction of a sleeper period results in decrease of generated ground vibrations for trains travelling at speeds below the velocities of Rayleigh surface waves in the ground (sub-Rayleigh trains). This effect can be used for reduction of generated ground vibrations in selected parts of the rail route. For trans-Rayleigh trains, the reduction of a sleeper period does not affect the vibration levels. Theoretical results are illustrated by numerically calculated frequency spectra of ground vibrations generated by single axle loads travelling at different speeds and by TGV, Eurostar and British high-speed trains.
Excessive ground vibrations associated with trains travelling at trans-Rayleigh speeds
Proceedings of the 4th European Conference on Noise Control (EURONOISE 2001), Patras, Greece, 2001
A very large increase in ground vibrations generated by high-speed trains (ground vibration boom) has been predicted theoretically in 1994 by the present author. The first experimental observation of this phenomenon was reported in 1997 by C. Madshus who worked with his team on the assessment of the newly opened high-speed railway line from Gothenburg to Malmo in Sweden. As the ground on the site of observation was very soft, the ground vibration boom could be observed for train speeds as low as 160 km/h. It is now well understood that excessive vibrations associated with ground vibration boom represent a serious hazard for the built environment, especially in the cases where high-speed lines are built on very soft soil. The present paper reviews the current status of the theory of ground vibration boom from high-speed trains. Among the problems to be discussed are contributions of different generation mechanisms, effect of track wave resonances on generated ground vibrations, effects of layered geological structure of the ground, waveguide effects of the embankments, and focusing of generated waves due to the track curvature. The results of theoretical calculations are compared with the existing experimental observations.
On the theory of railway-induced ground vibrations
Journal de Physique IV, 1994
In the present paper, the theory of generation of ground vibrations by moving train is considered. The theory takes into account contribution of each sleeper of the track subjected to the action of all wheel axles. Mechanical properties of the track and parameters of train and soil (including static contact nonlinearity of track-soil system) are taken into account. It is shown that generated ground-vibration spectra depend strongly on the periodicity of track (distance between adjacent sleepers), parameters of the train (train speed, distances between wheel axles and carriages), and on the axle loads of the carriages. A special attention is paid to the ground vibrations generated by superfast trains. It is shown that tremendous increase of vibration level may occur if the train speed exceeds the velocity of Rayleigh surface wave in the ground. Such a situation is not a fantastic one and may really happen, e.g., in the case of TGV trains for which the speeds of 500 km/h have been recently achieved on the experimental track in France. Simple methods of suppression of ground vibrations "on the track" are suggested.
Book: Ground Vibrations from High-speed Railways: Prediction and Mitigation
2019
Ground Vibrations from High-Speed Railways brings together leading international research on prediction and remediation of railway-induced ground vibration. It provides a unique general reference source which will help the reader to study the problem from different points of view, and provide answers to numerous theoretical and practical questions. Focusing specifically on the significant amplification of ground vibrations that can occur above critical speeds, the book provides a detailed guide to recent and ongoing developments in this area. Coverage includes: · Fundamental problems of dynamics of track-ground systems under the impact of high-speed trains · Effects of vehicle-track interaction and associated stability problems Railway-generated ground vibrations, including their impact on nearby buildings, effects of tunnels and layered soils · Modelling approaches, including 2.5D approaches, analytical and semi-analytical approaches, numerical approaches, hybrid models, and scoping assessment · Mitigation strategies, including soil replacement strategies, pile-supported embankments, use of stochastically rough surfaces. Ground Vibrations from High-Speed Railways provides in one volume the views of leading international experts on the problem of railway-induced vibration from high-speed trains and ways of reducing its environmental impact. It will be essential reading for all scientists and engineers working on prediction and mitigation of railway-induced vibrations.
Vibrational impact of high-speed trains. I. Effect of track dynamics
The Journal of the Acoustical Society of America, 1996
The dramatic increase in speeds of modern passenger trains makes it important to consider the vibrational impact of such trains on the built environment. In the author's earlier paper in which a quasistatic approach to the calculation of track deflection curves had been used ͓V. V. Krylov, Appl. Acoust. 44, 149-164 ͑1995͔͒, it had been shown that a very large increase in generated ground vibration level ͑about 70 dB, as compared to conventional trains͒ may occur if train speed exceeds the velocity of Rayleigh surface waves in the ground. Such a situation might arise, for example, with French TGV trains for which speeds over 515 km/h have been achieved. The present paper investigates the effect of track bending waves propagating in the system track/ground on railway-generated ground vibrations. It is shown that for train speeds approaching the minimal phase velocity of bending waves the level of generated ground vibrations is reduced. Theoretical results are illustrated by numerically calculated frequency spectra of ground vibrations generated by single axle loads traveling at different speeds and by TGV or Eurostar high-speed trains.
Quantification of ground-vibrations generated by high speed trains in ballasted railway tracks
Transportation Geotechnics, 2019
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.