ANISOTROPIC ELASTOPLASTIC UNDRAINED ANALYSIS OF SOFT CLAYS

A new model is presented for soft clays under un-drained loading. The model takes into account the dependence of both strength and deformability on stress history during consolidation of the clay. This stress history causes non-homogeneity with depth and anisotropic behaviour. The model includes a new failure condition in terms of total stresses. Parameters defining the proposed model are of two kinds: Intrinsic shear strength (based on Hvorslev's parameters), and stress history, namely, consolidation and overconsolidation pressures and at-rest earth pressure coefficient. The validity of the model is checked against different test results previously reported, covering different stress conditions (simple shear and unconfined compression tests with variable orientation). Finally, a finite element model has been developed, based on a hybrid method in displacements and stresses, which incorporates the proposed stress-strain-strength model for the clay. The case of a footing on a clay stratum over a rigid base is studied and the influence of the parameters of the model is analysed. © 1979, Thomas Telford Ltd. All rights reserved.