Effect of yield surface shape on the simulated elasto-plastic response of cohesive soils

Abstract

This paper presents a discussion on the effect of the selected yield surface shape on the simulated drained and undrained response of cohesive soils. The discussion is made possible by sequentially implementing two different yield surface shapes to a recently proposed elastoplastic critical state (reference) model, SANICLAY, as alternatives to its own yield surface. The reference yield surface shape of SANICLAY is a distorted and rotated ellipse, and the two studied alternatives have the shape of a distorted lemniscate and a distorted ellipsoid. For each constitutive model variant, the remaining equations of SANICLAY were retained unaltered. It is shown, that the use of the distorted lemniscate may lead to selectively more accurate simulations in comparison to the reference, but to a less accurate overall response with the same number of model constants. On the contrary, the use of the distorted ellipsoid provides an overall slightly enhanced simulative ability, but this at the cost of one extra model constant. © 2010 Taylor & Francis Group, London.