Preloading Ground Improvement For An International Container Terminal Project At Webb Dock Port Melbourne

In this paper, a case study is presented for preloading ground improvement for an automated stacking container development at Port Melbourne, Victoria, a reclaimed site underlain by high compressible marine clays referred to locally as Coode Island Silt (CIS). The paper has firstly reviewed the site reclamation history, followed by consolidation back analysis using PLAXIS 2D to study the historical settlements associated with the previous reclamation and land use and their effect on the future development with and without the adoption of preloading. A decision was then made to adopt a preloading program that involved the application of up to 5.5 m high compacted earth fill (110 kPa which is equivalent to more than twice of the maximum design load for the containers) for a period of 2 to 3 months, targeting to remove over 40% of the potential total settlement under the container stacking loads. The paper also discusses some of the instrumentation, such as settlement plates and vibrating wire piezometers that was employed to verify the target settlement. The study has concluded that the design intention has been achieved by the completed preloading ground improvement program.