Shallow Replacement Of Expansive Or Swelling Soils

A. Giannakogiorgos, F. Parodi, C. McDermott and D. Sullivan

In the June 2020 issue of NZ Geomechanics News ‘The Shrink Swell Test: A Critical Analysis’, Rogers et al., 2020, was published. This article provided an overview around the use of the Shrink Swell Test and current design practice for foundation design in NZ’s expansive soils in accordance with AS 2870:2011 site soil class.

This paper provides an additional summary of the currently existing methods/ways for identification of expansive soils (defined herein as soils susceptible to both swelling and shrinkage) and presents a discussion on recently observed construction practice comprising shallow 500mm replacement of expansive soils with compacted granular fill as a ‘measure’ to reduce the deformation of the expansive soils and mitigate the risk of structural damage to a slab foundation.