Stone columns inclusions are generally used to improve the mechanical properties of clays, for the purposes of reducing settlements, construction time and cost. The present paper is a part of a study on investigating the mechanical behavior of clay/sand column composites as represented by small laboratory specimens of medium clayey silt to silty clay reinforced by sand columns. Clay specimens with and without sand columns were tested in oedometer and shear box devices. The sand columns were inserted within the clay samples to achieve the area replacement ratio varied in the range of 10%, 20% and 30% of sample area. Mechanical characteristics of composite ground in terms of compression and shear resistance behavior were studied and compared with those of clay without sand column. Results indicated the importance of sand column replacement in improving the mechanical characteristics of tested clay. The positive effects of sand columns on both compressibility and strength are minimal for small area replacement ratios and gradually increases as the area replacement ratio increases.