Expansive soil is considered one of the most important causes of the collapse of buildings and facilities. There are many factors affecting the stability of structures constructed on expansive soils. In this paper, the numerical analysis was carried out on the swelling soil obtained from Al- Azhar university branch, Sohage government in Upper Egypt. Also, a parametric study was carried out to study the effect of some parameters like: the type of replacement, the thickness of replacement, and the ground water rise. It was found that using a replacement layer of sand only gives lower bending moment and shear force values than using replacement layers consisting of sand and gravel. Also, the maximum bending moment and shear force decreased as the ratio D/B increased. Moreover, the effect of groundwater level disappeared when the ratio D/B was greater than 3.0. Finally, Using sand as a replacement layer under foundations constructed on expansive soil dissipated the effect of the change in groundwater level.