Effect of fines content on steady-state strength of mixed and layered samples of a sand

This study has been carried out to determine how the fines content affects the steady-state line and residual strength of mixed and layered samples of a sand. A series of undrained monotonic and dynamic triaxial compression tests were conducted on reconstituted saturated samples of Ardebil sand with variation in fines content from 0 to 100%, using two types of test specimens; sand and silt mixed throughout the specimen and specimens with alternating sand-silt layers. The specimens were prepared in the loosest state using under compaction and water sedimentation methods of sample preparation. It is found that, as the silt content in both series of samples increases up to 35%, the steady-state line moves downward and the normalized shear strength is decreased. However, in layered samples with the same amount of silt as the mixed sample, the downward movement of steady-state line is greater. (C) 2003 Elsevier Ltd. All rights reserved.