Liquefaction of Silts and Silt-Clay Mixtures

Low plasticity silts and silty clays occur extensively in the central United States. For evaluating their liquefaction potential during an earthquake, no guidelines are available based on their density, void ratio, plasticity index, standard penetration values, or any other simple soil property. Their liquefaction behavior is not properly understood at present and is often confused with that of sand-silt mixtures. Pore water pressures and liquefaction in silt and silt-clay mixtures are discussed, and the influences of plasticity index on their cyclic strength are reviewed critically. It is concluded that considerable additional work is needed to fully understand the liquefaction behavior of these soils.