Juliette Florentin

Ground vibrations induced by InterCity/InterRegion trains: a numerical prediction based on the multibody/finite element modeling approach

This present paper aims to identify the main components which influence the generation and the propagation mechanisms of railway-induced ground vibrations. It is based on numerical assessments of ground vibrations on the L161 line that runs through Brussels Capital Region, Belgium. The objective is twofold. First, using data collection at a Brussels site, a numerical prediction model is built up. It is based on a two-step approach, recently validated in tramway and high-speed train cases and improved by an accurate description of the foundation. The vehicle/track/foundation and soil subsystems are treated successively. A key advantage of the new approach is that it is capable of including the effect of soil conditions in the vehicle/track simulation. The vehicle is modeled with the help of the multibody strategy. The soil is a three-dimensional finite/infinite element model, with a complex geometry on the surface and inclined soil layers. The track model includes a rail joint defect. The model is eventually validated against experimental data. Then, a sensitivity analysis on parameters of the studied site is performed. The vehicle and foundation modeling are discussed, along with the influence of local defects and vehicle speed variation on ground vibrations.

Prediction of Railway-Induced Ground Vibrations: The Use of Minimal Coordinate Method for Vehicle Modelling

This paper examines the combination of finite element method and multibody modelling to simulate the generation and propagation of ground vibration in the vicinity of railway networks. Based on the assumption that the source of vibrations lies at the wheel/rail contact, a multibody model of the vehicle is built using minimal coordinates, which leads to a system of pure ordinary differential equations, without constraint equations. Track and foundation dynamic equations are coupled to the vehicle’s equation of motion, using non-linear Hertzian theory. From these results, the ballast reaction on the subgrade is used in a second subproblem where free field ground response is computed using the finite element software ABAQUS.