Abstract: Dynamic compaction (DC) plus drainage is a new technology developed in recent years, especially in improving the hydraulic fill deposits. Based on the analysis of energy dissipation, soil compaction mechanism and the model of pore water pressure generated by impact loading, a simple but effective model is developed to simulate the process of dynamic compaction. A numerical program based on the finite difference method is developed to solve the boundary value problem under the condition of DC plus drainage. Development of pore pressure and the performances of compaction during DC are studied by the numerical results and compared with field data. Some factors affecting the performances of compaction such as hydraulic conductivity, time between impacts and distance of wick drains are discussed. Different effects between number of drops and impact energy per drop are also analyzed. The simulation results indicate that the proposed numerical model can simulate the process of DC with drainage. The development of excess pore water pressure and the reinforcement effect of soil can be predicted correctly. The drainage structure introduced in the DC technique can reinforce the deep soil and shorten the construction period. Finally, a design procedure is proposed to improve the practicality of DC and drainage technique.

Key words: dynamic compaction, drainage, numerical simulation, hydraulic fill deposits