Moisture tension in fine-grained reconstituted soils at high initial water contents - École des Ponts ParisTech Access content directly
Journal Articles Acta Geotechnica Year : 2020

Moisture tension in fine-grained reconstituted soils at high initial water contents

Abstract

The reclamation of land filled with high water content dredged clays is an important geological and geo-environmental issue. When designing such reclaimed land, the yield behaviour during compression is of paramount importance because it conditions the compressibility of soil and thus the final ground settlement. Previous studies suggest a significant effect of initial state of soils on their compression behaviour; in particular, the remoulded yield stress (identified when compressing reconstituted samples at high initial water content) decreased with the increase in initial water content. This phenomenon has been attributed to the effect of moisture tension. In fact, for a reconstituted soil at high initial water content, non-destroyed aggregates may exist in microscopic level although the degree of saturation of soil reaches 100% in macroscopic level. These aggregates can give rise to the generation of negative water pressure inside the aggregates, namely moisture tension. This moisture tension can greatly affect the mechanical behaviour of soil in the macroscopic level. With the destruction of aggregates, the moisture tension decreases. In order to verify this surmise, a series of experiments were conducted with moisture tension measurement on reconstituted Jossigny silt at three different water contents (1.0, 1.2 and 1.5 times the liquid limit). Meanwhile, mercury intrusion porosimetry (MIP) tests were conducted to analyse the macroscopic features. The test results proved the existence of moisture tension, and it decreased with increasing water content. When the aggregates are destructed completely, the moisture tension becomes zero. The non-intruded void ratio obtained from MIP tests was found to increase with decreasing water content, suggesting the destruction of aggregates by further hydration. Physically, the moisture tension corresponds to the water absorption potential of aggregates or the potential changes of aggregates from metastable state to true stable state. These observations provide experimental evidence supporting the existence of the remoulded yield stress identified for saturated reconstituted soils.
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Dates and versions

hal-03045953 , version 1 (08-12-2020)

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Wen-Jing Sun, Yu-Jun Cui, Zhen-Shun Hong, Han-Lin Wang, Ke Liu. Moisture tension in fine-grained reconstituted soils at high initial water contents. Acta Geotechnica, 2020, 15 (9), pp.2591-2598. ⟨10.1007/s11440-020-00934-8⟩. ⟨hal-03045953⟩
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