1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Railway traffic-induced vibrations are becoming one of the major environmental concerns in urban areas. Such vibrations may affect the quality of life of people settled in the vicinity of railway lines with frequent traffic. This paper contains the results from the research conducted by in-situ measurements and numerical modelling of railway traffic-induced vibrations. First, the transducers and the acquisition system are described and the methodology for processing of the measured vibrations caused by motion of trains is discussed. Then, a proposed numerical model based on the finite element method (FEM) is explained.
Numerical modelling of railway traffic-induced ground vibrations considers several mechanisms and a number of factors such as distance from the source, speed and type of traffic, quality of tracks, soil properties, properties of structures, etc. The proposed 3D FEM model for prediction of railway traffic-induced vibration is based on the elastic half-space theory. The soil’s Young’s modulus of elasticity and the Poisson’s coefficient can be normally estimated from the longitudinal and shear wave velocities obtained by geophysical measurements. Soil layers of different properties can also be included in the model. The basic problem of FEM simulation is the calculation of the predominant period of the elastic half-space. The analyses have shown that the forced-vibration method provides a more realistic prediction of the predominant period compared to that of the ambient-vibration method. The results from the FEM analyses have also been confirmed by using the standard empirical geotechnical model.
Apart from verification of the in-situ measurements, the proposed numerical model and analyses can serve as a tool in the practice of prediction of vibrations on a specific terrain. In such a way, possible measures for protection against vibrations can be undertaken. To illustrate the proposed methodology, site investigations and analyses carried out for the Kumanovo–Deljadrovce section are presented in the paper.