Sleeper End Resistance of Ballasted Railway Tracks

Abstract

This paper describes model tests carried out to investigate the contribution to the resistance to 11 the lateral movement of a railway sleeper attributable to the ballast shoulder, for a range of 12 shoulder widths and heights. During the tests, the deflection and resistance were measured 13 and photographs taken. Photographs were analyzed using a digital image correlation 14 technique to identify the zones of ballast surface disturbance, these demonstrate that a bulbed 15 failure volume is mobilized at the ultimate limit state. An idealised three dimensional failure 16 mechanism is proposed and resistances are calculated using the limit equilibrium approach. 17The calculation is found to provide a reliable estimate of the measured resistance. The work 18 identifies the optimum shoulder width and height. The calculations are extended to 19 demonstrate that when a number of sleepers are moved simultaneously the sleeper end 20 resistance may be 1/3 less per sleeper than that indicated in tests on an isolated sleeper. The 21 image analysis and limit equilibrium calculations show that this is due to the overlapping of 22 mobilized failure volumes from adjacent sleepers. 23

Numerical modelling of railway ballast at the particle scale

“…The DEM shapes used fell within the range of real particle forms for both the scaled and full size ballast. Also, a comparison of triaxial test results for scaled ballast (tests reported in this paper) and full size material (reported in the literature) confirmed that mobilized peak angles of shearing resistance for the scaled ballast were within the range of results reported for full size ballast [21].…”

Modelling the effects of trafficking and tamping on scaled railway ballast in triaxial tests

“…Modelling the effects of trafficking and tamping on scaled railway ballast in triaxial tests material reproduces satisfactorily key aspects of grain shape (Figures 4 and 5) and, at least in monotonic tests the strength of the full size material [24][25][26]. There will remain some differences between the relative grain shape performance and mechanical properties of the 1/3 size material and those of full size ballast.…”

A behavioural framework for fibre-reinforced gravel

“…This agrees with the findings of Sevi (2008). Physical model tests involving scaled ballast (which hereafter may be abbreviated to SB) have been used to investigate the development of plastic deformation under cyclic (Sevi et al, 2009) and moving wheel loads (Ishikawa et al, 2011); and how the dimensions of the ballast shoulder contribute to the resistance of a railway sleeper to lateral movement (Koike et al, 2014;Le Pen et al, 2014).…”