Collapse Potential Prediction and Characteristics of Unsaturated Sandy Soils

This study examined the effect of different parameters on the collapsibility of reconstituted sandy soils. The effect of related parameters including silt content, type of fines, initial water content, drying and wetting process, and wetting pressure have been studied. Collapse potential and matric suction were measured via the single oedometer collapse test and the ASTM filter paper method, respectively. The current study revealed that matric suction has a major role in determining the collapsibility of sandy soils. The effect of parameters related to soil index properties were reflected on the initial matric suction. In addition, an equation was proposed to predict collapse potential as a function of the two stress-state variables that control the behavior of an unsaturated soil, i.e. net normal stress and matric suction before wetting. The matric suction measurements were also used to generate soil water characteristic curves (SWCCs) based on the most widely used models. Finally, a simplified relationship between initial matric suction and the degree of collapse based was established.