Influence of Fines Contents on Soil Liquefaction Resistance in Cyclic Triaxial Test

Liquefaction is the most detrimental ground failure caused by strong earthquakes. Ground liquefaction leads to associated foundation and superstructure failures due to loss of bearing capacity and excessive deformation. An appropriate assessment of liquefaction is critical to the seismic safety evaluation of foundations and super structures. In this study, a series number of isotropically consolidated undrained cyclic triaxial test have been performed to evaluate influence of fines contents on soil liquefaction resistance. A total of 96 cyclic triaxial test was run on the uniform medium Monterey No. 0/30 sand with six different percentages of fine content. A total of 198 cyclic triaxial test was performed on the uniform medium concrete sand with five different percentages of fine content. Four different relative densities of 30%, 45%, 50% and 60%, two confining pressure of 103kpa and 207 kpa, six stress ratios (0.2, 0.25, 0.3, 0.35, 0.4 and 0.45) have been used for series of cyclic triaxial tests on two different soil types. Laboratory cyclic triaxial tests were conducted systematically to produce liquefaction potential curves.At a constant overall void ratio and PI, the increase in fines content up to 12% in the clean sand causes a decrease in liquefaction resistance. Beyond 20%, the further increases in fines content results in increase in liquefaction resistance. The threshold fines content, which is in the range of 12–20%, observed from nearly 300 of laboratory test results in this study. Statistical analyses were performed to formulate functional relationships for predicting liquefaction resistance of soils containing fines. For evaluating liquefaction potential for soils containing fines content, soil with 12–20% of fines content should be paid more attention.