Cyclic Behavior of Mixed Clayey Soils

Mixed clayey soils occur as mixtures of sand (or gravel) and clay in widely varying proportions. Their engineering behavior has not been comprehensively studied yet. An experimental program, comprising monotonic, cyclic, and post cyclic triaxial tests was undertaken on compacted clay granular material mixtures, having different proportions of clay and sand or gravel. This paper presents the results of cyclic triaxial tests and explains the behavior of the mixtures based on number of loading cycles, cyclic strain litude, granular material content, grain size, and effective confining pressure. The results indicate an increase in degree of degradation and cyclic loading induced pore water pressure as the number of loading cycles, cyclic strain and granular material content increase. Also the results show that the grain size has no significant effect on the degree of degradation and cyclic loading induced pore water pressure in the specimens. The effect of granular material content on pore water pressure during cyclic loading in equal stress level was also examined. The pore water pressure increases with the increase of granular material content.