Effective stress based bearing capacity equations for shallow foundations on unsaturated soils

The bearing capacity of shallow foundations is conventionally estimated using the equations derived for saturated or dry soils. Recent research shows a growing interest in the bearing capacity of unsaturated soils due to the conservative results of the conventional bearing capacity equations. In this study, alternative equations are proposed based on the effective stress principle, to estimate the bearing capacity of shallow footings on unsaturated soil considering both uniform and varied suction profiles. The validity of the proposed equations is established by comparing their predictions with experimental data available in the literature. The main purpose of this work is to provide equations those can be easily used by the practising engineers for preliminary or final estimations of bearing capacity of shallow footings on unsaturated soils. These equations require a small number of soil properties which can be easily obtained.