Influence of Non/Low-Plastic Fines and Associated Aging Effects on Liquefaction Resistance

The objective of the study presented herein is the development of an understanding of the influence of non/low-plastic fines and associated aging effects on the penetration resistance ($q_t$) and liquefaction resistance ($R_L$) of sandy soils. Towards this end, the authors performed a series of cyclic triaxial tests on samples having varying relative densities ($D_r$) and fines contents ($F_c$), wherein a miniature cone was incorporated into the triaxial apparatus. This allowed the penetration resistance and the liquefaction resistance to be determined directly for the samples. To simulate geologic aging effects, a small amount of cement was mixed in with the soil during sample preparation. From “unaged samples” without cement, it was found that although both $R_L$ and $q_t$ decrease as $F_c$ increases, a unique relationship exists between $R_L$ and $q_t$ that is independent of $F_c$. However, from samples having the same $C_c/F_c$ (i.e., simulating the same geologic age), it was found that $R_L$ increases as $F_c$ increases for the same $q_t$. This trend is consistent with field-based $R_L\mathrm{\text{-}}{q}_t$ correlations for natural soil deposits to which aging effects are intrinsic. Thus, it has been clarified that it is not the $F_c$-value by itself but rather the cementation effect associated with higher $F_c$ that results in a higher liquefaction resistance for a given $q_t$.