The relation between the state indices and the characteristic features of undrained behaviour of silty sand

The characteristic features of a series of isotropically and K-0-consolidated undrained triaxial compression behaviour of a silty sand were investigated for a range of initial void ratio (e) and mean effective confining stress (p'). The silty sand used in this study contained about 10% natural fines. The critical state line (CSL) of K-0-consolidated specimens, K0U was slightly lower than the CSL for isotropically consolidated specimens, CIU. The respective CSLs for K0U and CIU were used to define state indices, such as state parameter (psi), state index (I-s), state pressure index (I-p) and modified state parameter (psi(m)), within critical state soil mechanics (CSSM) framework. It was found that each state index exhibit a unique relation with liquefaction potential, irrespective of consolidation type, however different relationships were observed between state indices and the stress ratio at the triggering of liquefaction, eta(IS) is or the liquefaction resistance, q(IS). The correlation of characteristic features of undrained shearing (i.e., liquefaction potential, eta(IS) is and q(IS)) and drained shearing (maximum rate of volume change, (d epsilon(v)/d epsilon(a))(max)) with state indices were compared statistically in terms of root mean square deviations (RMSD). All characteristic features of undrained shearing generally showed the best correlation with I-p in term of RMSDs, however psi showed comparatively wider scatter for the specimens showing flow and limited flow behaviour. (C) 2019 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society.