Abstract: A sea levee over the thick mucky soft cohesive soils was improved by the blasting replacement method and both the short term and the long term settlement of the levee were analyzed using finite element method with laboratory test determined parameters. In the analysis, the riprap was modeled as the MohrCoulomb model and the soft soil was presented by modified Cam-Clay model. The riprap surcharge was placed on the improved soils and the settlement monitoring was performed in a 10 years after the completion of the levee. The monitoring and analysis results indicate that, after the riprap surcharge, the incremental stress in the soil increased significantly and the soft soil heaving were observed at both sides of the levee and the settlement was observed at the levee. The accumulative settlement after 621.2 days of the levee completion was 1.2 meters and the excessive pore water pressure was not dissipated completely. At time of 10 after the levee completion, the accumulative settlement was 1.55 meters. It is suggested that both the short term and long term settlements after the construction of the sea levee are significant, therefore, for the important sea levees, the control of the post construction settlement is very important.

Key words: Soft Soils, Blasting Replacement of Soil Soils, Settlement, Finite Element Method, Levees