Geopolymers show good promise for soft clay stabilization. This paper aimed to improve soft clay with geopolymer and evaluate the effects of geopolymer-stabilized columns on the mechanical and chemical behavior of the surrounding clay. Ranges of tests were conducted on both stabilized and unstabilized specimens to determine the impacts of geopolymer on the clay structure. The results showed that increasing the binder content and curing time significantly increased the unconfined compressive strength of stabilized samples. Microstructure and mineralogy analyses revealed that hardened materials were formed within the geopolymer matrix from the amorphous clay phases. In addition, the formation of the effective area around the geopolymer-stabilized columns resulted in the water content of soft clay decreasing while the undrained shear strength, pH, and electric conductivity values increased. Furthermore, the bearing capacity of soft clay dramatically increased (30-fold) due to an increase in column area.