Applicability of the concept of equivalent intergranular void ratio to sand-plastic fines mixtures below threshold fines content

The technical note presents findings of an experimental study on the applicability of equivalent intergranular void ratio e*eq concept in sand-plastic fines mixtures under monotonic and cyclic loading. The results of undrained triaxial tests conducted on mixtures of Hostun sand with varying amounts (0% to 20%) and types of plastic fines (kaolin and calcigel bentonite) were already presented in two previous studies. The e*eq for the mixtures under various initial densities was calculated using the parameter b. Preliminary results show that the concept of e*eq seems to hold valid in the e-p space considering monotonic tests as well as being able to capture the variation of the cyclic resistance ratio for a predefined number of cycles to initial liquefaction from cyclic undrained tests even in mixtures with plastic fines below threshold fines content. However, the need for further studies is duly acknowledged.