Alternative design approach for soft clay improved by PVDs

In this paper the design procedures for multi-stage construction based on the research know-how described by Rujikiatkamjorn and Indraratna (2009) are proposed. The length of a vertical drain, anisotropic soil permeability and vacuum pressure are considered and a reduction in consolidation time through vacuum preloading is compared to other available methods. Design charts eliminating cumbersome iterative procedures are then developed using the equivalent drain diameter as an independent variable to obtain the relevant drain spacing. The design examples based on the land reclamation project at the Port of Brisbane for both single and multi-stage construction are also given.