Abstract: The factors that might contribute to the weakening of the soft soils underneath the breakwater dike are discussed and the possible solutions are also presented in this paper. The improvement effect of using Prefabricated Vertical Drains (PVD) has been numerically analyzed. Based on the equivalent degree of consolidation, the threedimensional problem is converted into plane strain problem. The numerical analyses are validated by the insitu measurement.

Key words: Breakwater, Soft Soil Foundation, Plastic Drain Plate, Drainage Consolidation, Numerical Simulation