Treatment of Collapsible Soils by Salts Using the Double Consolidation Method

Collapsible soils are unsaturated soils which present a potential for large deformation and a complete change to the whole particle structure after wetting, with or without loading. These soils are characterized with loose structures composed of silt to fine-sand-size particles. Collapsible soils are deposited in arid and semi-arid regions. Due to the expansion of human activities, these regions are occupied aggressively leading to the use of large quantities of water, which creates favorable conditions for soil collapses. Theses soil failures lead to severe damage and large distress to man-made structures. The objective of this experimental study is to illustrate that the mechanical resistance of collapsible soil can be improved. This study demonstrates that it is possible to minimize the collapse potential Cp to an acceptable level after chemical treatment with salts (ammonium sulfates (NH4)2SO4 and potassium chlorides KC1) at different concentrations (i.e., 0.5, 1.0, 1.5 and 2.0 mole/liter) and under different compaction energies. The method used in this study is based on oedometric tests with variable normal stresses.