Embankment design and construction for a major rail upgrade project in Western Australia

Srijib Chakrabarti, Lani Cheenikal and Gurpreet Singh

Australia is one of the largest iron ore producing countries in the world. As a result of increased international demand for iron ore, development of new open pit mines with associated infrastructure has been on the rise in Western Australia. Design and construction of new rail lines and duplication along existing rail lines have been one of the key issues for timely delivery of iron ore from mine to port. This paper presents geotechnical issues associated with the design and construction of a major rail duplication project in the Pilbara Region in Western Australia that include cuts and embankments up to 20 m in height. The geotechnical issues include geotechnical investigation, sourcing borrow materials for construction of embankments including sub ballast capping, slope stability, settlement and construction methods. A variety of rock formations were encountered along the alignment comprising igneous, sedimentary and volcanics with variable degree of weathering. Slope stability assessment was undertaken using limit equilibrium method, kinematic analysis concept and visual assessment. Deformation analyses were undertaken using PLAXIS computer program. Geotechnical investigation, selection of parameters for engineering analysis and method of design during the construction stage are discussed in this paper.