Water retention characteristics of swelling clays in different compaction states

ABSTRACT

The soil–water retention (SWR) characteristics of the clays play an important role in controlling their engineering behaviour, particularly, in the unsaturated state. Although, researchers have attempted to understand the water retention characteristics of the clays in their reconstituted or remoulded state, such studies are rare for the clays in their intact state. In this context, it becomes important to understand the influence of initial state of compaction, which would create different pore and fabric structure (viz., microstructure), on the water retention characteristics of the clays. With this in view, SWR behaviour was experimentally determined for the swelling clays (dried from different compaction states, viz., intact, reconstituted and remoulded) by employing Dewpoint PotentiaMeter (WP4C®). The changes in the pore size distribution of the clays at different stages of drying cycle were also studied by employing the Mercury Intrusion Porosimetry. The study reveals that the SWR curves for the intact and reconstituted specimens of the clays converge beyond a certain stage of drying. Also, a critical analysis of changes in the pore structure of the swelling clay specimens, during drying, indicates that the progressively deforming pore structure plays an important role in controlling its water retention characteristics to a great extent.

KEYWORDS:

• Swelling clays
• state of compaction
• soil–water retention curve
• Dewpoint PotentiaMeter
• microstructural studies

Acknowledgement

The authors wish to acknowledge the support of the European Commission via the Marie Curie IRSES project GREAT – Geotechnical and Geological Responses to Climate Change: Exchanging Approaches and Technologies on a worldwide scale (FP7-PEOPLE-2013-IRSES-612665).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors wish to acknowledge the support the European Commission via the Marie 499 Curie IRSES project GREAT – Geotechnical and Geological Responses to Climate Change: 500 Exchanging Approaches and Technologies on a worldwide scale [FP7-PEOPLE-2013-IRSES- 501 612665].