Stress path effects on the strength behaviour of a layered soil

An experimental investigation dealing with the influence of stress path on the shear behaviour of a layered soil prepared in the laboratory is described. Specimens trimmed in vertical and horizontal directions have been sheared under three different stress paths in compression and extension tests. Either in compression or extension, the stress–strain behaviour of the specimens with both orientations was apparently the same, although the volume change behaviour was different. The effective stress parameters C′ and [Formula: see text]′ were found to be unique and independent of the stress path and two principal orientations. However, the values of [Formula: see text]′ in extension tests were 6–7° higher than those in compression tests.