This lecture aims to demonstrate and discuss some major aspects related to stabilizing ballasted rail tracks overlying soft soils using artificial inclusions such as geosynthetics, recycled rubber mats, and end-of-life tyres. The use of geocomposites (i.e., bonded geogrid-geotextile layers) to enhance the performance of ballast is de-scribed with the aim of reducing track settlement, increasing the resilient modulus, and decreasing ballast degradation. The effects of increasing the confining pressure on rail track behaviour, particularly with regard to particle breakage has been studied using large-scale laboratory tests. We are therefore presenting a novel solution of confining the upper sub-ballast layer (capping) with energy-absorbing recycled rubber tyres to increase the stability and resiliency of track substructure. This study confirms that a sub-ballast layer confined by recycled rubber tyres can actively reduce ballast breakage within the track substructure. This study also carried out numerical simulations using finite element method (FEM) to examine how end-of-life tyres to improves track performance. The outcomes of this study will lead to a better understanding of how artificial inclusions-reinforced ballasted tracks perform, and then to a cost-effective track design with improved safety and passenger comfort.
Distinguished Professor Buddhima Indraratna (FTSE, FIEAust, FASCE, FGS, FAusIMM) is a civil engineering graduate from Imperial College, London, and obtained his PhD from the University of Alberta in 1987. He worked in industry in several countries before becoming an academic and has been a United Nations Expert and Foreign Advisor to numerous overseas projects. Prof Indraratna’s pioneering contributions to Ground Improvement, Soft Soil Engineering and Transport Geotechnology and various other aspects of geotechnical engineering have been acknowledged through numerous national and international awards, including the 1st Ralph Proctor Lecture and 4th Louis Menard Lecture of the International Society of Soil Mechanics and Geotechnical Engineering, ISSMGE; The Engineers Australia Transport Medal in 2011, Thomas Telford Premium Award, 2015 (ICE, UK); 2009 EH Davis Memorial Lecture of Australian Geomechanics Society; and 2014 CS Desai Medal for his substantial and sustained contributions to Transport Geotechnics and Ground Improvement, respectively. Recently, he was the recipient of the 2017 Outstanding Contributions Medal of IACMAG. The New South Wales Minister of Transport awarded Professor Indraratna the 2015 Australasian Railway Society’s Outstanding Individual Award at the State Parliament. Distinguished Prof Indraratna has developed unique process simulation laboratory equipment for geomaterials and computational methods for predicting the dynamic response of transport infrastructure. His research has influenced national and international technical standards pertinent for large scale testing, transport embankments, port reclamation and site investigations.
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