Abstract
The unconfined compression strength test for soils can be used to determine the modulus of subgrade reaction k (sub unc) in the laboratory. It proves more economical and saves time compared with in situ plate loading tests. The modulus obtained from such tests is considerably lower than the modulus obtained from consolidation tests due to the absence of lateral confinement. Stress-subgrade reaction modulus graphs (sigma -k) are presented which show the behavior of k during loading. Some typical k (sub unc) values are given and also Kc values, the slope of the sigma -k curve. Design values of foundations with dimensions B and L can be calculated by using proposed methodology.