EFFECTS OF DIFFERENT CONSOLIDATION CONDITIONS
ON LIQUEFACTION RESISTANCE AND SMALL STRAIN QUASI-ELASTIC
DEFORMATION PROPERTIES OF SANDS CONTAlNlNG FINES

JUNICHI KOSEKI and AKIRA OHTA

ABSTRACT : In order to investigate the effects of different consolidation conditions on liquefaction characteristics of sands containing fines, a series of undrained cyclic triaxial liquefaction tests was performed on artificial samples prepared by mixing Toyoura sand and bentonite at a ratio of 95% to 5% by dry weight. Some specimens were isotropically consolidated for I , 20 or 100 days at a regular temperature, while the others were consolidated for 2 or 5 days while heating the cell water up to 60 degrees centigrade. Over-consolidated specimens with OCR of 2 and 4 were also prepared at a regular temperature. During consolidation and cyclic triaxial shearing of several specimens, their quasi-elastic deformation properties were measured while applying very small amplitude cyclic axial loads. Longer consolidation time, higher temperature during consolidation or higher ratio of over-consolidation resulted in an increase in the liquefaction resistance, with the exception that the liquefaction resistance of specimens consolidated for 100 days was not larger than that of specimens consolidated for 20 days. On the other hand, such different consolidation conditions affected the change in the quasi-elastic deformation properties in different manners. Development of cementation was suggested to have occurred during consolidation under high temperature. Reduction in the extent of anisotropy was suggested to have occurred during over-consolidation, which was accompanied by a decrease in the negative dilatancy at the initial part of shearing.

Key words : consolidatron conditions, fines, Iiquefaction, sand, triaxial test, Young's modulus (IGC: D6/D7)