New Zealand Geotechnical Society (NZGS) Symposium 2021
The existing literature contains no shortage of attempts at defining ‘collapsible soils’, all largely focussed on outlining the often unique properties and conditions required for collapse settlement to take place. First recognised and studied by Jennings and Knight (1957), collapse settlement can, in its simplest form, be considered as the radical rearrangement of soil particles upon wetting to result in a significant reduction in the total volume of the soil mass. Show more…It is this behaviour, and subsequent impact on structures founded within such materials, that make the timely identification and accurate characterisation of collapsible soils significant to the geotechnical professional.
This paper provides a brief overview of the collapse settlement phenomenon as documented in the existing literature. It includes a discussion of published findings regarding the potential for collapse settlement to occur in New Zealand soils, and some of the more widely recognised methods used to:
1. Identify the potential for collapse settlement to occur on site (i.e. recognising materials which may have a ‘collapsible’ fabric and which, under particular conditions, may undergo collapse settlement),
2. Assess the potential severity of collapse settlement (qualitative evaluation), and
3. Assess the potential magnitude of collapse settlement (quantitative evaluation).
The paper concludes with a brief discussion of collapse behaviour from an effective stress perspective and why this should be considered when assessing collapse settlement
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