Cyclic shear response of undisturbed and reconstituted Fraser River Silt

摘要

The cyclic shear response of natural low-plastic Fraser River silt was investigated under constant volume direct simple shear loading using specimens from undisturbed samples and by reconstitution of the same material. During monotonic shear loading, the reconstituted specimens exhibited a generally weaker stress-strain response compared to those displayed by the undisturbed specimens. The results of the cyclic tests also demonstrate that the specimens of undisturbed silt, despite having a looser density under identical consolidation stress conditions, exhibited more dilative response and larger shear resistance compared to those displayed by reconstituted specimens. These observed differences between the undisturbed and reconstituted materials suggest that commonly used state variables e and σ_v~' alone are not sufficient to determine the shear behaviour of low plasticity silt. The differences in the behaviour can be attributed to the difference in particle structure (soil fabric) between the undisturbed and reconstituted specimens.