Soft Ground Stabilisation – Vacuum Consolidation via Vertical Drains
Prof Buddhima Indraratna
Conventional surcharge loading to achieve soft soil consolidation has been a relatively slow process, and the combination of part surcharge and vacuum pressure with prefabricated vertical drains (PVD) has become an attractive alternative in many parts of the world. Centre for Geomechanics and Railway Engineering at University of Wollongong is one of the leading soft soil testing and ground improvement centres in the world, and the use of large scale experimental rigs, theoretical development and numerical simulations of soft clay improvement with vacuum preloading via vertical drains have contributed to significant advancement of the design techniques during the past decade.
The lecture will look at the inevitable problems of smear associated with mandrel driven PVD, the distribution of suction pressures through PVD, conceptual development of consolidation models capturing the effects of vacuum. The applications to case histories employing equivalent plane strain theory developed by Prof Indraratna and his research team will be presented and discussed. The Lecture will also address the role of PVD under cyclic loads in railway environments and the optimization of drain lengths under various circumstances. The field observations of retarded pore pressure dissipation will be interpreted in terms of drain unsaturation, high lateral strains and other factors. Finally, design procedure with associated charts for PVDs with vacuum combined surcharge pressure will be introduced.
About the speaker
Prof Buddhima Indraratna Professor of Civil Engineering and the Director of Centre for Geomechanics, University of Wollongong
Prof Buddhima Indraratna is Professor of Civil Engineering and the Director of Centre for Geomechanics at the University of Wollongong. He is a graduate in Civil Engineering from Imperial College, University if London, and holds a PhD from University of Alberta, Canada in Geotechnical Engineering. He is a Fellow of the Institution of Engineers Australia, Fellow of American Society of Civil Engineers and a Fellow of the Geological Society, UK. He represents Australia in several international Technical Committees and Working Groups in the areas of Soft Soil Engineering and Natural Disaster Prevention and Control. He has published over 300 refereed articles and 4 research-based books, and has delivered over 25 Keynote presentations at international conferences. He has successfully supervised more than 30 PhD graduates, a number of them currently working in Queensland. He has been an active consultant for various geotechnical projects in Australia and overseas, including road embankments and railways built on very soft clays.
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