The mechanical properties of a high plasticity expansive clay
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Published version
Author(s)
Type
Journal Article
Abstract
The mechanical properties of a high plasticity expansive clay from South Africa are reported. The experimental programme considered wetting after loading tests followed by one-dimensional consolidation and unloading of undisturbed and statically compacted samples. The results of this study illustrate that laboratory preparation of expansive clays do little to alter the soil's swell characteristics. This finding is attributed to the fact that, due to numerous swelling and shrinking cycles over a geological time frame, expansive clays tend to have reworked fabric in-situ.
The effects of structure are also assessed in both undisturbed and compacted specimens by comparison of the various consolidation tests with that of a reconstituted sample. The results illustrate a gradual yielding process for both undisturbed and compacted specimens, indicating progressive disruption of structure. After consolidation, while the expansion indices were found to be similar for both compacted and undisturbed samples, measured values were lower than that of the reconstituted specimen. Such a result is indicative of some preservation of structure after testing. It is also emphasised that consolidation tests on expansive clays are likely to exist in structure permitted space if swelling strains are restricted during the inundation process. Conversely, for most results presented it is seen that the swell caused by the inundation phase is approximately as disruptive to structure as laboratory preparation and compaction.
The effects of structure are also assessed in both undisturbed and compacted specimens by comparison of the various consolidation tests with that of a reconstituted sample. The results illustrate a gradual yielding process for both undisturbed and compacted specimens, indicating progressive disruption of structure. After consolidation, while the expansion indices were found to be similar for both compacted and undisturbed samples, measured values were lower than that of the reconstituted specimen. Such a result is indicative of some preservation of structure after testing. It is also emphasised that consolidation tests on expansive clays are likely to exist in structure permitted space if swelling strains are restricted during the inundation process. Conversely, for most results presented it is seen that the swell caused by the inundation phase is approximately as disruptive to structure as laboratory preparation and compaction.
Date Issued
2022-06-20
Date Acceptance
2022-03-24
Citation
Engineering Geology, 2022, 303
ISSN
0013-7952
Publisher
Elsevier BV
Journal / Book Title
Engineering Geology
Volume
303
Copyright Statement
© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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Publication Status
Published
Article Number
106647
Date Publish Online
2022-03-28