EFFECT OF THE PARTICLE SIZE DISTRIBUTION AND PLASTICITY ON ACCURACY OF THE LIQUEFACTION PREDICTION IN MIXED SANDY SOIL

Abstract

 Liquefaction prediction of the mixed sandy soil containing fines content is conducted based on the liquefaction strength derived from the N-value. The N-value is corrected depending on the fines content (Fc) and plasticity index(Ip). The previous research shows that the sand’s uniformity coefficient affects the correlation between the N-value and liquefaction strength. This research aims at thoroughly investigating the influence of particle size distribution and fines content on the accuracy of liquefaction prediction in mixed sandy soil. A series of undrained cyclic torsional shear tests and prototype-scale standard penetration tests were conducted using 5 base materials having different particle size distributions. The quantity of Fc and Ip was also changed in each stage under the tests. By comparing the experimental results, it is found that the accuracy of liquefaction prediction varies by the quantity of Fc in cases of mixed sandy soil containing silt. The particle size distribution of the base material has also been shown to influence the accuracy of liquefaction prediction in cases where the mixed sandy soil contains clay.