Analysing Foundation on Port Said Soft Clay Stabilized by Deep Mixed Columns

Port Said is characterized by the presence of thick layers of soft clay. Particularly inSouth of Port Said, soft clay strata extend from the ground surface to few tens of meters making it not possible to use conventional ground improvement methods, as soil replacement. Deep Mixing Method(DMM) is an alternativemethod with relative advantage as it does not require full soil replacement and can be used when soft soil layers extend deeply up to 40 m. This paper aims to study the effectiveness of using deep mixed columns (DMC) to improve the bearing capacity and to reduce settlements below embankments and light structures in South of Port Said. Numerical analyses on hypothetic embankment and raft foundation models were performed using finite element packages PLAXIS. A parametric study was performed to assess the influences of different parameters on DMCeffectiveness. The study showed that the installation of DMC is very effective in reducing settlement and lateral movement of South of Port Said deep soft clay strata particularly for low area ratios of DMC. On the other side, DMC installation generates zones of shear and effective stress concentration. From the studied parameters it was noticed that DMC effectiveness to reduce settlement increases linearly with DMC depth and with stiffness ratio between DMC and soil. 10% area ratio was found optimum for settlement reduction while16 meter DMC depth was optimum for lateral movement reduction