الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Deposits of collapsible soils provide many challenges to foundation designers. One of the most important challenges is predicting the collapse settlement or evaluating the collapse settlement for a previously constructed structure begins to experience distress. Also, the estimating of the depth of wetting zone front strongly affects the accuracy of predicting the collapse settlement.
The thesis overviews laboratory infiltration tests which have been performed to predict the extent of wetting zone within a collapsible soil. During these tests, the rainfall water was simulated in laboratory to investigate the infiltration of rain water around and beneath an unloaded footing model resting on collapsible soil; Distribution of soil water content and matric suction beneath and around the footing model were assessed. Consequently, accurate details of the progression of wetting zone front were obtained. The effects of the initial dry unit weight of the formed soil, the initial water ’content of soil, the intensity of induced water, and the percentage of fines in soil are studied. A relationship between depth of wetting zone and time was established, and a proposed mathematical formula for predicting the fInal depth of wetting zone or the depth of wetting zone front at any time are presented.
The effects of the studied parameters on the properties and shape of the soil¬water characteristics curve of the formed soil were also observed.
In addition, the effect of the applied stress on the footing model on the progressio~ of wetting zone front and the distribution of soil water content and matric suction was investigated.
To get a closed-form equation for predicting the collapse settlement due to wetting caused by rainfall, experimental study has been conducted. During these tests, the rainfall water was simulated in laboratory and the depth of wetting zone front and the collapse settlement of a loaded square isolated footing model were measured. The effects of the initial dry unit weight of the formed soil, the initial water content of soil, the intensity of rainfall water, the percentage of fines in soil, and the applied stress on footing model were studied. Relationships between collapse settlement versus time and collapse settlement versus depth of wetting were investigated. Proposed formulas for predicting the expected final collapse settlement, or collapse settlement at any time in terms of the studied parameters are presented.
Also, the experimental data was used to investigate a relationship between the collapse settlement Qf a loaded square isolated footing model and the matric suction measured within the wetting zone through a collapsible soil. Different parameters affecting the response of a footing resting on collapsible soil were studied. For each studied case, the progression of the wetting zone front was investigated and the distribution of water content and matric suction with depth were determined. The thesis presents a proposed mathematical formula relating the collapse settlement at any time or the expected final collapse settlement with the matric suction and the thickness of wetted soil.