In geotechnical investigation, determination of the bearing capacity of foundation soil constitutes is
an important task. Most of the previous studies investigated the stability of such foundation system
using classical bearing theory. The classical bearing theory was developed depending on the theory
of plasticity with the assumption that the soil behaves as a rigid-plastic material. The bearing
capacity theories require making a guess on the shape and geometry of the most critical failure
surface (mechanism of failure) a priori. Most theories assumed the geometry of the failing soil mass
is symmetrical with respect to the center of the footing, while, Krey suggested that the geometry of
the failing mass is unsymmetrical. Numerical methods do not require an initial assumption the
geometry of the failure mode. In the present work, a numerical study assisted by a computer
program is carried out using (Krey’s method) to investigate the center of the slip circle gives the
minimum bearing capacity of the footing. Also, PLAXIS 2D used for analysis of some cases of
studies by Krey’s method. Krey it's of the present study is compared with the classical theories of
the ultimate bearing capacity. The predicted values of ultimate bearing capacity of soil of this study
are less than those of others theories of ultimate bearing capacity. In order to facilitate the
calculation of bearing capacity the proposed equations are used. It is a function of (footing width,
(B), ratio of footing depth to its width, (Rf) , angle of internal friction of soil, (