Frontier technologies in design and construction for sustainable transport infrastructure

Abstract

Railways are expected to be one of the main modes of future transport in rapidly developing countries with high population densities, including Sri Lanka. In spite of recent advances in rail track geotechnology, ballasted tracks progressively degrade under heavy cyclic and impact loading. Field studies often provide significant knowledge to better understand track performance and to extend the current state-of-the-art in design. Therefore, comprehensive field trials were carried out on two instrumented rail tracks in Bulli and in Singleton, New South Wales, Australia. In these studies, several track sections were reinforced with different types of geosynthetics placed beneath the ballast embankment, with the aim of reducing track settlement, increasing track resiliency, and decreasing ballast degradation. The effects of impact loads and its mitigation using shock mats are discussed. A series of isotropically consolidated drained triaxial tests were conducted on both clean and clay-fouled ballast with varying fouling levels to establish the relationship between the extent of fouling and the associated strength-deformation properties. The outcomes of this research are now elucidated in view of industry practices. This keynote paper provides a fresh insight to design and performance of rail tracks capturing particle degradation, fouling and the use of geosynthetics in track design.