Design of Shallow Square Foundations Using Saturated and Unsaturated Soil Parameters

The design approaches in shallow square foundations generally based on Prandtl and Terzaghi bearing capacity theory. Other investigators who deal with this subject have already developed their design with adding or changing design parameters on this approach. Within thirty years investigators try to find out effect of saturation degree on bearing capacity of foundation. Especially, in semi-arid and arid region determination of bearing capacity using saturated state bearing capacity equations produces over design for foundations. In this study, using commercially finite element analysis software (SIGMA/W), the effects of suction pressure and saturation degree on shallow foundations have investigated. The necessary design parameters, which are used in the finite element program, are obtained in the laboratory studies in İstanbul Technical University. According to this research, it is recognized that the bearing capacity of foundation using unsaturated soil parameter has increased comparing to design with saturated state design parameter. These results encourage the designers using unsaturated soil parameters especially in arid and semi-arid regions.