A collapsible soil has relatively high strength in dry condition but gaining large settlements when soaking without any increasing in normal stress on itself so easy occurrence of differential settlement. Thus to determine and to predict the collapse potential is our objective. The specimens are reconstituted condition by controlled the initial dry density and water content. The results from laboratory test and model give the same prediction the collapse potential that decreases when initial dry density increase and the location of maximum value is around normal stress at soaking between maximum past pressure in dry and saturated condition.
One of the most problematic unsaturated soils is the collapsible soil, which is a common geotechnical concern in arid regions. Although these relatively high void-ratio soils exhibit a significant strength and low compressibility at their natural, in-situ water content, they collapse significantly upon wetting under load. The decrease in soil suction and weakening of bonds associated with accidental or intentional wetting triggers the collapse. Most often, the damage to constructions results from differential deformations, which had not been anticipated at the design and construction stages. Therefore, the estimation of the collapse settlements which linked with the collapse potential and shear strength become major components in the moisture-sensitive soil sites. A laboratory or field test is commonly used for structuring the model to estimate the collapsible potential settlements of soils under a certain rainfall condition. Many researchers have already carried out the studies on the collapsible behaviors of unsaturated soils from theoretical and practical points of view (e.g. Chen et.al., 1999, El- Ehwany & Houston, 1990, Fredlund & Rahardjo, 1993, Habibagahi & Mokhberi, 1998, Nishimura et.al., 1998, Tadepalli & Fredlund, 1991 and Sharma & Singhal, 2006).
