The use of dynamic compaction to remove/reduce risks due to collapse compression and seismicity in silty fine sands at smelter site in Iran

This paper describes the novel use of Dynamic Compaction (DC) to remove collapse compression potential in a desiccated crust and its partial success in removing liquefaction potential at a smelter site in Iran. The S.I. generally revealed either very silty sands or very sandy Silts overlying a marl bedrock at a depth of between zero and 12 metres below finished facility ground level. There was generally a stiff crust of silty fine sands across the whole site with loose to very loose horizons just above and below the ground water table. A foundation loading test showed collapse compression on inundation (settlement at a stress of 270 kN/m2 increased from 110 to 150 mm on flooding). Due to the marginal nature of the soil from a ground improvement point of view an extensive preliminary test programme was implemented.