The design of structures on cohesive soils requires a quantitative understanding of the clay-structure interactions under anisotropic stress-strain conditions. This research develops experimental methods to determine the effects of anisotropy in clays. Rational analyses of complex clay-structure interaction problems (mat foundations, braced excavations, tunnels, etc.) are not feasible without adequate data on undrained and drained response of clay deposits. This study develops a "generalized" constitutive relationship incorporating the stress-strain anisotropy. This research uses a unique Directional Cell (DSC) device to fully control the major principal stress direction by varying the normal and shear stresses and acting on four faces of a cubical soil sample. The study employs both undrained and drained testing at varying overconsolidaiton ratios and determines how "initial" anisotropy of consolidated clays change due to subsequent straining that causes plastic deformations.
