This paper introduces the assumptions, procedure and results of a number of three dimensional numerical analyses for simulating the behavior of an encased, versus unencased, stone column group installed in a very soft soil layer; the finite element technique is employed for this purpose. Settlements and lateral deformations (so called bulging) of stone columns are selected as criteria for judgment and comparison of the behavior of the ordinary and geosynthetic encased stone columns (GEC’s). Also, parametric studies and analyses are carried out to investigate the effects of parameters such as stiffness and length of the geosynthetics as well as modulus of elasticity and friction angle of the column’s material on the mechanical behavior of the group of GEC’s. The results indicate that increasing the stiffness of the encasement clearly enhances the behavior of the group of GEC’s. The results also showed that the performance of the GEC’s is comparatively less sensitive to values of internal friction and modulus of elasticity of the column’s materials. Moreover, complementary analyses suggested that encasing only the outer columns of a group is very efficient in providing an optimal design, both economically and technically.