Deformation Characteristics of Railway Roadbed and Subgrade Under Moving-Wheel Load

Abstract

To develop a relevant performance-based design method for railway asphalt roadbed, the resilient and residual deformation characteristics of railway roadbed and subgrade were investigated by means of scale model tests. In the scale model tests, the difference in the mechanism between moving-wheel loading and fixed-point loading were discussed. The deformation characteristics of roadbed and subgrade in the fixed-point loading which apply cyclic vertical load at a fixed point on rails above a certain sleeper was proved to be substantially different from the trend in behaviour when moving a wheel repeatedly on a model rail as in the full scale railway track. Therefore, it was concluded that the moving-wheel loading test is necessary to investigate the deformation characteristics of railway roadbed and subgrade. On the other hand, the result of moving-wheel loading test showed that the resilient deformation characteristics do not change even residual deformation caused by repeated loading. A resilient deformation characteristic of asphalt roadbed is an important factor because the fatigue criterion of asphalt concrete is specified in terms of resilient tensile strain. The resilient deformation characteristics of asphalt roadbed, including the maximum resilient tensile strains in the asphalt concrete layer, were simulated well by linear elastic FEM analysis using exact boundary condition and relevant material parameters described in this paper.

Mechanistic-empirical permanent deformation models: Laboratory testing, modelling and ranking

“…While small scale models of railways were introduced in the past (Momoya Y. et al, 2005, Al Shaer A. et al, 2008, several models focusing on the development of permanent deformation of railways under cyclic loadings or moving loads at low speed (Bian et al, 2014) are currently available. However, the field measurements and numerically calibrated results show that increased train speed has a huge influence on the long-term performance of a structure (i.e., higher dynamic stresses and higher permanent deformation).…”

Simple plastic deformation analysis of ballasted track under repeated moving-wheel loads by cumulative damage model

“…However, Brown (1996) suggested the importance of principal stress axis rotation on the performance of pavement and railway track. Hirakawa et al (2002) and Momoya et al (2005) showed that the behaviour of substructures in the principal stress axis rotation field differs from that in the fixed principal stress axis field, and they demonstrated that the rotation of principal stress axes has a strong influence on deformation-strength characteristics of coarse granular materials. Therefore, when developing a numerical model for predicting the mechanical behaviour of track structures, it is important to give a special consideration to the effect of principal stress axis rotation.…”

“…For example, as for experimental studies, a variety of loading tests with model track and model ballast have been previously performed by many researchers (e.g. Raymond and Bathurst, 1987;Chan and Brown, 1994;Indraratna et al, 1998;Kohata et al, 1999;Anderson and Key, 2000;Hwang et al, 2001;Hirakawa et al, 2002;Momoya et al, 2005;Suiker et al, 2005;Lackenby et al, 2007;Anderson and Fair, 2008;Powrie et al, 2008). In general, there are two types of loading methods when performing model tests and laboratory element tests to examine the mechanical behaviour of railroad ballast, namely fixed-point loading mode and moving-wheel loading mode.…”

Model Test Study on the Influence of Train Speed on the Dynamic Response of an X‐Section Pile‐Net Composite Foundation

“…erefore, it is necessary to introduce a moving load into experiments. Momoya et al [9] conducted a laboratory experiment using a 1 : 5 ballasted track model and studied the distribution characteristics and settlement development of stress inside the subgrade under a moving load, but the simulated train speed was only 42 km/h. Al Shaer et al [10] constructed a 1 : 3 ballasted track model containing three sleepers, adopted an M-shaped wave to represent a bogie load, and studied the relationship between the subgrade settlement and sleeper vibration acceleration.…”