A dyke construction was dealed with geotextile-encased sand columns. The dyke was used to enclose a polder in Hamburg-Finkenwerder, Germany. With the help of geotextile, the columns can be used in very soft soils, even undrained shear strength c(u) < 15 kN/m(2), without excessive bulging. After the system is installed, the dike can be filled immediately. To analysis observed data of the long-term settlements in the dyke, three stages can be gotten i.e. "Primary settlements" - "Secondary settlements" - "Creep settlements". Most settlements occurred during the primary filling, while, only little settlements appeared after that construction was accomplished. The settlement rate decreases from the first settlement stage to the last one. No jump takes place when unloading soft soil. Furthermore, the method shorten time and saved a lot of money.