THE HYDROLYSIS CHARACTERISTICS AND COMPRESSIBILITY OF SOFT CLAY SOIL IMPROVED USING VCM

Soft clay is identified to have some unfavorable characteristics when used as the foundation for construction work. This is due to the low bearing capacity and high compressibility which often leads to prolonged consolidation settlement. Therefore, soil improvement is necessary, and this can be achieved through the Vacuum Consolidation Method (VCM). This research focused on conducting laboratory-scale model tests to determine the characteristics of clay soil improved by vacuum consolidation in terms of its physical properties, hydrolysis, and compressibility. The results showed that the water content decreased as soil approached the Prefabricated Vertical Drain (PVD). A similar trend was also observed for the compression index value; this is because local density occurs in the soil near the PVD as a result of the movement of fine particles towards the PVD, which fills the empty pore space. Moreover, soil permeability in both vertical and horizontal directions reduced, and the soil became anisotropic after VCM improvement. The results of this research can be a consideration in the use of the VCM method for soft soil improvement, especially the problem of clogging zones that occur due to the suction pressure of the vacuum pump, which can reduce the performance of the VCM.