A family of improved yield surfaces and their application in modeling of isotropically over-consolidated clays

Recognizing the limitation of the existing yield surfaces for clays, a novel type of the yield surface is derived. The shape parameters allow for the distortion of the yield surface from an ellipse to a teardrop shape such that it provides more flexibility for better modeling the shear response for over-consolidated clays. A new bounding surface model has been proposed within a critical state framework, and can predict the realistic behavior of over-consolidated clays under both undrained and drained conditions. The capacity of the model is demonstrated by five different reconstituted clays with representative testing results in the literature.