A Simplified Numerical Model for the Assessment of Vibration in Subway Lines with Experimental Validation

Abstract

The first studies on the dynamic behavior of railway lines go back to the 19th century, after the industrial revolution. Since then, numerous analytical solutions and numerical models have been developed toward understanding the dynamic response of moving loads. However, proposals that reproduce the vibrational behavior of subway lines remain challenging due to the complexity and number of variables involved. This paper presents two simplified numerical models built and validated with experimental data to simulate the subway dynamic behavior. The first simulated the vibration generation, whereas the other simulated the propagation throughout the soil. Analyses were conducted from 1/3 octave bands spectra, as in practice. The models showed the coefficient of friction of the wheel/rail contact does not impact the global level vibration significantly, and an estimation of this parameter (0.3) enabled an analysis of the attenuation conditions for the floating slab track (FST) system. The study of attenuations revealed FST stiffness changes are a more robust solution than changes in its mass. The wave soil propagation model has proved adequate in comparison to classic solutions, and a strategy for the estimate of error associated with two-dimensional (2D) simplifications is proposed. Despite the simplicity of the models, the numerical simulations fit the experimental data well, supporting simplified models that study subways, and promoting more vibration control evaluations at lower computational costs.