ABSTRACT
Inundation settlement or wetting collapse is triggered by the rise of groundwater table. The complexity of this soil volume change behaviour is that it is taking place under effective stress reduction. In partially saturated soils, the void spaces are filled with both air and water, therefore suction force exists between the soil particles resulting to the increase in shear strength. When the soil is inundated the effect of suction is diminished and the soil shear strength reduced to the shear strength at saturation. The effect of this reduction in strength is anticipated to have the prime influence on this settlement behaviour. The role of shear strength in governing soil settlement is incorporated in Rotational Multiple Yield Surface Frame-work. The framework is able to model settlements due to loading and wetting. A laboratory scale tests of a model footing were conducted to study the effect of groundwater fluctuation on the soil settlement in tropical residual soil. Three types of test have been conducted: (1) the soil is loaded to failure (2) the soil is loaded and inundated (3) the soil is loaded, inundated and subsequent lowering of water table. The framework is used to predict the soil settlement behaviours. The results show good agreement between the predicted and the modelled settlement. These result shows that the Rotational Multiple Yield Surface Framework is able to model soil settlements in both conditions; loading and wetting for saturated and unsaturated soil conditions.
