A finite element model was developed to investigate the effect of installing stone columns by vibro-process on post-installation soil state of stresses, in a back analysis fashion. Field test load data was utilized as the basis for this analysis: instead of determining the soil response to the test load, based on known initial soil stresses and material properties. The analysis was inversely posed to determine the soil initial stresses, based on the recorded system settlements and the post-installation material properties. The alteration in the soil state of stresses due to stone columns installation is represented by the variation in Ko. A cavity expansion numerical solution was attempted to simulate the installation mechanism, and the corresponding changes in Ko were assessed. Both types of analyses showed that the post-installation horizontal to vertical stress ratio, K*, significantly exceeds the at rest value of Ko.