RELATIONSHIP BETWEEN LIQUEFACTION STRENGTH OF SAND WITH FINE FRACTION AND VARIOUS VOID RATIOS

Abstract

Liquefaction damage has been reported in the ground containing fine fractions. It is necessary to investigate the effect of soil containing fine fractions on liquefaction strength. This study aims to clarify the relationship between the liquefaction strength and the skeleton void ratio, representing the skeletal structure of the soil and the fine fraction void ratio. For the utilized samples, Toyoura sand was used as the coarse fraction, Kaolin clay worked as the fine fraction, and mixed soil in which the mixing ratio was altered in the range of 0 to 40% was applied. Besides, considering the difference in the fine fraction properties, the experimenter made use of Fujinomori clay, Kasaoka clay, and the three combined soils. The specimens were prepared using the dry tamping method and repeatedly subjected to cyclic undrained triaxial tests. As a result, when the skeleton void ratio does not exceed the maximum void ratio of sand, it is located on the same line as the liquefaction strength regardless of the types of fine fractions. We can declare that it is a unique relationship. When the skeleton void ratio exceeds the maximum void ratio of sand, there is an excellent correlation between the fine fraction void ratio and the liquefaction strength. However, In the region with skeleton void ratio es exceeding the maximum void ratio emax of sand alone (es >emax), liquefaction strength tends to be different depending on the plasticity index Ip of fine fraction.