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Rail CRC work: Mechanics of ballasted rail tracks - a geotechnical
perspective
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Under Rail CRC Project 6/139
‘Ballast-track interaction and the effective use of recycled
ballast with geosynthetics for improved track design and enforced
drainage’
Rail CRC researchers have completed extensive work on ballast
degradation, evaluation of geotechnical properties of recycled
ballast, the examination of different methods of improving soil
formation and preventing clay pumping and the development of a
numerical model based on finite element analysis.
As a result of the leading work undertaken by Rail CRC researchers
on this project, the first book to stem from Rail CRC research has
been published, entitled ‘
Mechanics of Ballasted Rail Tracks: A Geotechnical
Perspective’.
Published in late 2005 by
Taylor & Francis
, the book has been commended as ‘the only book that deals
in detail with the degradation of ballast under static and dynamic
loads’.
The Rail CRC work incorporated in the book includes a guide to the
design of track ballast for railway engineers, covering track
structure and loading, factors governing ballast behaviour, testing
of ballast, use of geosynthetics, existing deformation models, a
new model for ballast, track drainage, track maintenance and
recommending ballast gradings.
Strong validation of the Rail CRC research includes the decision in
late 2005 by Arup Geotechnics to utilise outcomes of Rail CRC
research in the development of a new rail track being built at
Sandgate, near Newcastle in New South Wales. A one-kilometre
stretch of the line is over deep, soft estuarine deposits and it is
on this section which large-scale formation soil testing and
sophisticated computer modelling will be undertaken to predict the
track behaviour in the short and long term. Arup’s
incorporation of Rail CRC research is in addition to the recent
decision by industry partner RailCorp to adopt new ballast
gradations based on the research, which are expected to reduce
track deformation and save the company substantially in track
maintenance.
The research was independently assessed by STEM Partnerships in
2006 and was estimated to have the potential to deliver a
risk-free-value of $67.2 million over 15 years to the rail
industry. Taking into account the risks involved in delivering the
technology and processes, the expected value is estimated at $39.1
million. The benefits of the research to track owners include
reduced maintenance costs for ballast repair and lower capital
costs of new track (by straightening out curves by being able to
traverse difficult terrain). For train operators benefits include
fewer speed restrictions due to ballast problems, reduced incidence
of track closure due to ballast problems and straighter tracks
reducing capital costs and operating costs.
