Stress-Strain Properties of Compacted Clays

The increasing use of finite element techniques for deformation analyses of embankments has resulted in a need for a more quantitative description of the stress-strain behavior of such soils. Data from more than 200 triaxial tests on samples of compacted clay, loaded under unconsolidated-undrained conditions, are analyzed using the hyperbola originated by Kondner. The stress-strain curves are expressed in terms of the initial tangent modulus and strength, both of which are then related to confining pressure. Poisson's ratio was related to stress level (σ₁ - σ₃)/(σ₁ - σ₃)_f, and then to confining pressure. The resulting general analytic expression was a good representation of the stress-strain curves in about 80% of the tests. The best correlations were found for specimens compacted in the range of water content typically encountered in the field.