The calculation of surface foundations is usually governed by two conditions, one referring to settlement and the other to foundation ″stability″ . For this second condition, the bearing capacity of the foundation is derived from the knowledge of the strength-criterion defining the admissible stress-states for the soil, then the admissible load for the foundation is restricted to a fraction of this bearing capacity, by means of a safety factor. This paper deals with the bearing capacity problem. It aims at improving the corresponding state of knowledge both in classical and nonclassical cases, leading to a better approach of the safety-factor and making the calculation of foundations possible in circumstances for which no sufficient information was previously available. Refs.