Abstract: Fine content is one of the main factors that affect the shear strength of the sand. A series of true triaxial shear tests of the fine sand mixed with various amounts coarse sand are conducted. Both the fine sand and coarse sand are selected form the Fujian standard sand. The sand mixtures are consolidated and drained tested confining pressures of 100kPa and 300kPa, respectively. The results show that the shear strength of the samples at the initial stage of shear is not quite different under both the low confining pressures and the high confining pressures. After a strain hardening process, both pure coarse sand and pure fine sand demonstrate a very high strength. But when the samples are the mixtures of coarse and fine sands, the fine particles at the edge of the coarse sand skeleton serve as a role of roller. The shear strength of coarsefine sand mixtures reduces with the increase amount of fine sand content.

Key words: Fine Contents, Sandy Soils, True Triaxial Shear Device, Shear Test