الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Moisture movement above water level in the vadose zone plays a particularly important role in the performance of shallow foundations, because of the large seasonal changes in the moisture condition of the soil close to the earth’s surface. Especially, estimating the changes in the moisture condition for paved roads is required in the design and performance prediction of roads and airfields. This thesis investigates the possibility of calculating the moisture movement beneath shallow foundations for light structures under coupled non-isothermal conditions. The thermal and moisture flow in soil act in a parallel and complex manner and must be considered together. The moisture migration problem and storage in soils is quite complicated especially when coupled with heat transfer in the soil. A numerical two-dimensional model of these processes is developed to model moisture migration beneath pavements. The numerical model developed using Vadose/w, finite element software, is a coupled model with non-isothermal conditions and climatic data introduced as boundary conditions. The developed approach was validated using the Long-Term Pavement Performance (LTPP) database. LTPP database for the pavement performance in Collins, Mississippi in the United States contains moisture content and temperature measurement beneath the pavement used to calibrate the numerical model developed. The storage function is solved and convergence and stability are investigated, and it is concluded that the numerical procedure is convergent and stable in general. Then, Transient coupled analyses were conducted on typical two-dimensional pavement model using Vadose/W computer software using climatic conditions collected for Cairo, Egypt. The results helped understand the various conditions affecting moisture variation beneath covered areas in Egypt and provided valuable results that can be incorporated in various pavement design models to achieve tangible measures for the effect of water content changes. In general, this study highlights the importance of accounting for the effect of local environmental conditions in the design of the shallow foundations of light structures.