Designing High-Speed Train Railway Embankments Using Finite Element Analysis

Isfendiyar Egeli, Handan Usun

Arabian Journal for Science and Engineering, December 2012, Volume 37, Issue 8, pp 2127-2136

 

Abstract

Design and construction of high-speed train railway (HSTR) infrastructure is different from that for normal trains, since high geometric standards and material properties are involved. For example, HSTR embankments are designed to limit total-differential settlements to minute amounts. In this study, a typical ‘slab-track’ type HSTR embankment was used to investigate the replaceability of one fill strata known as ‘uncemented-prepared-subgrade layer’ (U-PSL), constructed by using a locally obtained medium sand, as opposed to various ‘cemented-prepared-subgrade layers’ (C-PSL), whose mixes were prepared at two water-to-cement (w/c) ratios and three cement contents (c). Three size cylindrical samples were cast, 7–28 days water cured and were tested to obtain the unconfined compressive stresses, strains, elasticity moduli and Poisson’s ratios at failure. Test results were then fed into the Plaxis-FEM program to find the maximum total settlements of individual layers and compared with the requirements. Only three C-PSL mixes having cement contents (c) of 20, 25, 30 % and water-to-cement (w/c) ratios of 0.4 and 0.5 met the strict settlement criteria. The study showed that the original (h = 2 m) thick U-PSL can be replaced with 0.3h-m thick C-PSL at w/c = 0.5 (i.e. h = 0.6 m). Likewise, the original (h = 2 m) thick U-PSL can be replaced with 0.2h-m thick C-PSL at w/c = 0.4 (i.e. h = 0.4 m). Also, the extra effort of doing in situ soil compaction and testing in layers is reduced or eliminated. This would give not only alternative ways to HSTR embankment designers/constructors, but also substantial savings in construction time and costs.

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