Simulation of dynamic compaction processes in saturated silty soils

Dynamic compaction (DC) is a widely used ground improvement technique for densification of loose granular materials. Densification of treated deposits is achieved through high-energy impacts to ground surface. For saturated deposits, soil skeleton deformation and intergrain slippages, due to impact, cause an increase in pore water pressure leading to local liquefaction around the impact zone. In highly pervious sands, this induced pore pressure dissipates rapidly, concurrently reducing void ratio and increasing soil density. Supplementing saturated low permeable non-plastic silty deposits with drainage provisions such as wick drains improve the efficiency of DC to densify such soils and improve their resistance to liquefaction, load bearing, and settlement characteristics. A numerical simulation model has been developed to analyze the ground response and densification of saturated non-plastic silty soils during DC. Visualization tools have been developed to view and analyze changes in pore pressures and density profiles in the vicinity of the impact zone during DC processes. The simulation model and visualization tools have been used in developing design charts. Theses tools are expected to advance the use of DC for liquefaction mitigation in silty soils. Copyright ASCE 2006.