Ground Improvement for Rail, Port and Road Infrastructure--From Theory to Practice

The transportation infrastructure in coastal regions of Australia has been expanded in recent years due to high population density and increased traffic volume. Such expansions require the application of ground improvement techniques to improve performance and sustainability of the infrastructure. In this paper, innovative ground improvement techniques applicable to railway embankments, port reclamation and embankment fills are discussed. For ballasted rail tracks, the performance of different types of geosynthetics for improving the stability and drainage of railway tracks under high cyclic loading is investigated. Instrumented tracks were conducted to measure the in-situ stresses and deformations of ballast at Bulli, New South Wales (NSW), Australia. Furthermore, stabilization of soft formation soils underneath rail tracks using prefabricated vertical drains (PVDs) is also studied through finite element analyses and field measurements at Sandgate. The innovative use of the mixtures of coal wash (CW) and steel furnace slag (SFS) as the reclamation fill is demonstrated through laboratory and field investigations at the Outer Harbor extension of Port Kembla in Wollongong, NSW. The optimum CW-SFS mixtures that may meet most of the geotechnical specifications are proposed to be used as an effective structural fill. Finally, the design of the combined vacuum and surcharge fill system and the construction of the road embankment are described using a case study from the Pacific Highway upgrade project. Field data are presented and interpreted to demonstrate how the embankments performed during construction in both vacuum and non-vacuum areas.