Effect of silt content on cyclic and post-cyclic behavior of saturated loose sand

Since most natural deposits are a combination of sand and fine grains and as man-made geotechnical structures like tailing dams have a high percentage of cohesive and cohesionless fine grains, the study of cyclic and post cyclic behavior of these soils is essential. For saturated sands, the effect of non-plastic fine grains (silts) on their monotonic and cyclic behavior has been investigated. A majority of studies are related to monotonic and cyclic loading and post-cyclic loading has received less attention. In this paper, the effects of silt content and different Cyclic Stress Ratios on the cyclic and post-cyclic behavior of saturated loose sand are investigated. The sand used in this study is Firuzkuh silty crushing sand, which is abbreviated to sand . All samples were prepared so that their relative density was about after consolidating. The experiments were performed using the saturated cyclic triaxial apparatus. Suitable preparation of specimens was one of the most important factors in the accurate performance of triaxial tests. The cyclic and post cyclic tests on mixtures made of sand with silt were undertaken following the recommendation of D4254. Changes in pore pressure coefficient, liquefaction resistance, stress-strain curves, and stress path in clean and silty sand ( silt) were recorded. Results show that the tested samples become liquefied in a smaller number of cycles by increasing the until they show softening behavior at larger when effective stress rapidly drops to zero. In lower , the stress-strain curve is collapsible while in larger , loops expand and they indicate more damping of materials.