Highway embankments stability during its service period represents an important factor for the safety of highway users and vehicles. Consequently, the cost of construction of these embankments should be adequate to maintain the safety and durability during this period through proper estimation of the loading on asphalt pavement, slope stability, horizontal and vertical deformation, etc. Slope stability of the embankment mainly depends on the shear strength of the soil layers materials; this shear strength is affected by the water table level through the contribution of the capillary water. Negative pore water pressure above the water table level evolves matric suction in the unsaturated zone above water table; this matric suction increases the shear strength of the soil depending on the soil type, void ratio, etc. This paper studies the slope stability of highway embankment using finite element method analysis to show the effect of the presence of water table and the contribution of the matric suction. A trial slope is shown to have same factor of safety with reduced cross section due to increasing the shear strength hence, reducing the cross-sectional cost is determined.
