ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 6 September 2011
Page Count: 8

On The Shear Behavior of Ballast-Geosynthetic Interfaces

Indraratna, Buddhima
Professor of Civil Engineering, School of Civil, Mining & Environmental Engineering, Univ. of Wollongong,

Karimullah Hussaini, Sd. K.
School of Civil, Mining & Environmental Engineering, Univ. of Wollongong,

Vinod, J. S.
Lecturer in Civil Engineering, School of Civil, Mining & Environmental Engineering, Univ. of Wollongong,

(Received 15 August 2010; accepted 29 July 2011)

Abstract

Large-scale direct shear tests were performed to explore the behavior of rail ballast-geogrid interfaces and establish the role of geogrid aperture size on the interface shear strength. Fresh latite ballast with an average particle size (D₅₀) of 35 mm, and seven geogrids with equivalent aperture sizes ranging from 20.8 to 88 mm were used for this current study. The laboratory experimental results confirm that the interface shear strength is influenced by the geogrid aperture size. The interface efficiency factor (α), defined as the ratio of the shear strength of the interface to the internal shear strength of the ballast varies from 0.8 to 1.16, and the ballast-geosynthetic interface friction angles vary from 52 to 67°. Moreover, a criterion to determine the minimum and maximum aperture sizes required to generate the beneficial effects of the geogrid has been identified in this study.

Keywords:
ballast-geogrid interfaces, aperture size, geogrid, interface shear strength, interface efficiency factor, interface friction angles

Paper ID: GTJ103317
DOI: 10.1520/GTJ103317
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