This research project conducts a systematic investigation of the parameters affecting the efficiency of dynamic compaction in granular soils. The experimental phase will include large-scale laboratory tests with dynamic measurements of soil pressures and tamper acceleration during impact, and static measurements of strains within the soil mass following each tamper drop. These measurements are essential or the analysis of the dynamic soil-tamper interaction. The analytical phase will include the development of a dynamic model for the analysis of soil behavior under impact loads. In addition, a finite element computer code with dynamic elastic-viscoplastic large strain constitutive model for soils will be used. Laboratory and field test results will be compared with the analytical model and the finite element analysis results. The final goal of this study is the fundamental understanding of the mechanism of dynamic compaction and the development of rational engineering guidelines for design.