Factors Affecting Liquefaction Triggering of Granular Soils in Laboratory Testing

In practice, liquefaction assessment is driven by earthquake case histories, but the case-history database is limited and there are important gaps in the information available. As a result, laboratory tests have continued to play a key role in determining how various factors influence liquefaction triggering. This paper presents an investigation into how factors such as particle size, particle size distribution, and preparation method influence cyclic liquefaction triggering. Eleven particle size distributions of a natural soil and tailings, ranging from pure silt to fine gravel, were tested in cyclic simple shear. The results were cast in the critical state framework and compared with a large body of data from the literature to understand how the choice of testing method influences the cyclic resistance. The results suggest that the widely used constant volume cyclic simple shear tests produce significantly lower liquefaction resistance values than either cyclic triaxial tests or the case history database. Simple shear tests are not as sensitive as cyclic triaxial tests are to a wide range of factors, including overburden stress, particle size, particle size distribution, and specimen preparation method.