The effect of Kaolinite clay on the liquefaction resistance of the sandy soil; case study of the Gorgan city in north of Iran

In this paper by performing of a series of triaxial cyclic test the effect of adding fines on the liquefaction potential of sandy soil are studied, after sampling of the soil and doing basic geotechnical tests on the samples. The result of triaxial cyclic tests showed that pure sandy soil after 54 cycle of loading is liquefied which prove the studied soil is liquefaction prone. Moreover it can be inferred from the test results that in low fine percent liquefaction resistance is decrease that can be attributed to breaking the coarse grain’s bond by fine particles. While by increasing the percent of the Kaolinite clay the soil liquefaction resistance is increase which can be explain by domination of the fine in soil structure and making soil more cohesive. This decreasing and increasing trend in soil resistance against liquefaction by adding fines is observed in several other studies which the percent of the fine that change the trend is named threshold fine amount. The result of the paper has been shown for studied sand of Noor city the threshold fine amount of Kaolinite clay is 12 weight percent.