Estimation of liquefaction potential from dry and saturated sandy soils under drained constant volume cyclic simple shear loading

Understanding the liquefaction mechanism of sandy soils still remains as one of the challenges in geotechnical earthquake engineering, since clean sands, silty sands and clayey sands do not necessarily show identical reactions under seismic loading. This study investigates the cyclic simple shear responses of three sandy soils: clean sand (Sile Sand 20/55), silty sand (Sile Sand 20/55 with 10% IZ silt) and clayey sand (Sile Sand 20/55 with 10% kaolin) based on many dry and saturated specimens. Drained constant volume cyclic simple shear tests on clean and silty sand specimens have shown that liquefaction potential of those soils could also be determined via dry samples. This is an important observation, since dry specimens are much easier to prepare and less time consuming compared to their saturated counterparts, as the demanding saturation process is eliminated. However, cyclic responses of dry and saturated clayey sand specimens were shown to be quite different, and therefore saturation of these specimens is still a must for liquefaction assessment. For both silt and kaolin, adding 10% fines to the base sand increased the liquefaction potential of resulting sandy soils considerably compared to the clean sand at the same void ratio. But this difference relatively decreased as the specimens became looser.