EVALUATION OF LIQUEFACTION OF SANDY SOILS BASED ON CONE PENETRATION TEST

Soil liquefaction is a major concern for structures constructed on sandy and silty sites.Soil liquefaction is also a major design issue for large structures such as mine tailings impoundments and earth dams.Therefore,liquefaction evaluation plays an important role in seismic investigation and design of buildings.It is important to determine the soil stratigraphy and in-situ soil state for soil liquefaction.Because of the difficulty and cost constraint of obtaining high-quality undisturbed sand samples,the in-situ test is a perfect method to evaluate the potential for soil liquefaction.At present,numerous methods based on the cone penetration test(CPT) data have been developed for evaluating the potential of soil liquefaction,but the validity is still confused.As a new kind of in-situ test,the piezocone penetration test(CPTU),is receiving increasing attention for assessing the soil liquefaction potential because of its repeatability,reliability,continuous data tracing and cost effectiveness.The methods for evaluating liquefaction potential of soils using in-situ tests are reviewed based on the precious works.Two comprehensive CPTU-based methods for assessing liquefaction resistance of sandy soils are evaluated and compared on the basis of data collected on nine sites in Jining—Xuzhou Expressway,where the actual field performances against liquefaction from CPT data are used as referenced data.It is shown that Robertson method and Olsen method are considered to be fairly accurate in predicting liquefaction resistance of sandy soils.The Robertson method is slightly more accurate than the Olsen method.