Design of ballasted railway track foundations using numerical modelling. Part I: Development

Abstract

In this paper, a new design method for ballasted railway track foundations is developed, which can sustain high speed trains and heavy axle loads. The proposed method is intended to prevent two most common track failures, namely the progressive shear failure of track subgrade and excessive plastic deformation of track substructure (i.e., ballast + subgrade). The method is based on improved empirical models and sophisticated three dimensional (3D) finite elements (FE) numerical analyses. The improved empirical models are used for predicting the cumulative plastic deformation of the track, whereas the stress parameters of the ballast and subgrade layers are obtained from the 3D FE numerical analyses. The outcomes are then synthesized into a set of design charts that formed the core of the proposed design method so that it can be readily used by railway geotechnical engineers for routine design practice. The design method can be applied to various practical conditions of train-track-ground systems, including the modulus, thickness and type of ballast and subgrade. In addition, the traffic parameters which have a significant influence on track performance are also considered in the design method, including the wheel spacing, train speed, and traffic tonnage. The new design method has significant advantages over the existing methods and offers a major role in modern railway tack design and code of practice.The applications of the new design method are presented and explained in a companion paper (i.e., Part II: Applications).

A comparative study of the response of buried pipes under static and moving loads

“…Ground surface spring elements (viscous dampers) were used in the sides and the bottom of the model to model the infinite boundary conditions. This technique is used to eliminate the effect of S and P wave reflection (Sayeed and Shahin, 2016;Sayeed and Shahin, 2017). The damper properties with respect to the P wave ( ) and S wave ( ) are calculated automatically in MIDAS GTS/NX using Equations 1 and 2, respectively (MIDAS IT.…”

Investigation into Some Design Aspects of Ballasted Railway Track Foundations using Numerical Modelling

“…The train geometry and standard axle loads used in the FE model were selected to be for the X-2000 HST [20], as shown in Figure 2. The train moving loads were modelled in accordance with Araújo [21] in which the rail FE nodes, which are rigidly connected to the sleepers via pads, were subjected to a wheel load (denoted as loading nodes) whose value changes in time (note that the spacing between any two loading nodes is 0.6 m).…”

Nonlinear Vibration of Axially Loaded Railway Track Systems Using Analytical Approach

“…Partial differential equations are used for mathematical representation of beams resting on the linear or nonlinear elastic foundation. [15][16][17][18][19][20] Generally, finding an exact solution for nonlinear vibration equations is very difficult. Javanmard et al 21 implemented Energy Balance Method (EBM) to the Euler-Bernoulli beam resting on an elastic foundation.…”

“…Partial differential equations are used for mathematical representation of beams resting on the linear or nonlinear elastic foundation. 15–20 Generally, finding an exact solution for nonlinear vibration equations is very difficult. Javanmard et al.…”