AbstractThis paper investigates the behavior of shallow foundations with different base shapes on expansive soils under various Stresses conditions and different slopes of the base. Expansive soils are soils that undergo significant volume changes due to variations in moisture content, which can cause severe damage to structures built on them. The shape of the foundation base can influence the magnitude and distribution of the soil pressures, as well as the deformation and cracking of the foundation. The paper presents a numerical analysis using a finite element method with Plaxis 3D. The paper also proposes some recommendations for the optimal design of foundation base shapes on expansive soils. The numerical results show that the foundation base shape has a significant effect on the stress and displacement distributions in the soil and the foundation and that some shapes perform better than others in terms of reducing the soil pressures. The paper provides some useful insights for the design and construction of shallow foundations on expansive soils.