A Binary Packing Material–Based Procedure for Evaluating Soil Liquefaction Triggering during Earthquakes

This paper presents a new approach to assess the liquefaction triggering of saturated sandy soils based on comprehensive laboratory datasets in conjunction with the concept of binary packing material for sandy soils. The equivalent skeleton void ratio ($e_{sk}^{*}$) is used as an alternative state index for sandy soils with fines content ($FC$) less than a threshold value ($F{C}_{th}$). To characterize the liquefaction triggering curve for the correlation between the cyclic resistance ratio (${\mathrm{CRR}}_{15}$) in 15 cycles and the corrected shear-wave velocity ($V_{s1}$), a series of undrained cyclic triaxial tests as well as bender element tests have been performed on six types of saturated sandy soils. A remarkable finding of the laboratory investigation is that both ${\mathrm{CRR}}_{15}$ and $V_{s1}$ are virtually uniquely related with $e_{sk}^{*}$ for all six sandy soils. This finding is confirmed by the experimental data on ${\mathrm{CRR}}_{15}$ and on $V_{s1}$ for different sandy soils published in the literature. The parameters defining the relationships between ${\mathrm{CRR}}_{15}$ and $e_{sk}^{*}$ between $V_{s1}$ and $e_{sk}^{*}$ can be simply determined through a unique set of explicit expressions which incorporate some basic index properties of the host sand and fines. In this regard, the proposed procedure provides a significant advantage in the evaluation of liquefaction triggering of sandy soils in practice.