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Volume Variation In A Clayey Soil Depending On Water Content And Compaction: An Experimental Approach


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A. Guarnieri & G. Lorenzini


The present paper performs a laboratory analysis of the swelling/shrinking behaviour with water of a vertisol collected at Baricella, near Bologna (Italy). This required an experimental apparatus to be realised and tested to monitor the mutual affections between the soil-fluid dynamics parameters. Lower initial water contents and higher initial degrees of compaction proved to enhance the swelling evidence. A phenomenological analysis is also provided within the paper. Further tests also on soils with different properties are felt necessary to widen the field of application of this approach. Keywords: void ratio, moisture ratio, swelling, shrinkage, compaction. 1 Introduction In soil-fluid dynamics and, more generally, in agriculture the problem of describing the behaviour of swelling soils as they come in contact with water is particularly felt as: 1) almost every soil shows, up to a certain extent, swelling properties; 2) by irrigating the fields or even in case of rain the contact of swelling soils and water is unavoidable and, more, is necessary; 3) if a soil swells then its internal cracks are forced to widen and this causes an intense mechanical action on the roots of the crops that could lead to a breakage and so a to a severe damaging of the harvest; 4) the variation of the soil pores dimensions consequent to swelling determines an internal water potential changing that can dramatically modify, even without a homogeneous distribution, the suction force exerted by a crop to get water by means of its roots. Despite its clear relevance, tackling the topic of swelling dynamics has never been a very popular research


void ratio, moisture ratio, swelling, shrinkage, compaction.